Built-in tools reference

Overview

The built-in tools below are owned by the meerkat-tools builtin dispatcher (build_builtin_dispatcher / BuiltinDispatcherConfig in meerkat-tools/src/builtin), which is the source of truth for tool names, categories, and gates.

Tool	Category	Default	Gate	Description
`task_create`	Task	Yes	—	Create a new task
`task_get`	Task	Yes	—	Get a task by ID
`task_list`	Task	Yes	—	List tasks with optional filters
`task_update`	Task	Yes	—	Update an existing task
`shell`	Shell	No	—	Execute a shell command
`shell_jobs`	Shell	No	—	List background shell jobs
`shell_job_status`	Shell	No	—	Check background job status
`shell_job_cancel`	Shell	No	—	Cancel a background job
`memory_search`	Memory	N/A	`memory-store-session`	Search semantic memory
`datetime`	Utility	Yes	—	Get current date/time
`apply_patch`	Utility	Yes	—	Apply structured file patches inside the project root
`view_image`	Utility	Yes	`image_tool_results`	Read an image file and return base64 content
`generate_image`	Image generation	Runtime-backed	image provider profile	Generate or edit assistant images and commit blob-backed image blocks
`blob_save_file`	Blob files	Runtime-backed	blob store	Save decoded blob bytes to a project-root-contained file
`blob_load_file`	Blob files	Runtime-backed	blob store	Load a project-root-contained file into the realm blob store
`blob_inspect`	Blob files	Runtime-backed	blob store	Inspect blob media type and decoded byte size without returning bytes
`send_message`	Comms	Yes	`comms`	Send a collaboration message to a peer
`send_request`	Comms	Yes	`comms`	Send a structured request to a peer
`send_response`	Comms	Yes	`comms`	Send a response to a peer request
`peers`	Comms	Yes	`comms`	List discoverable peers (trusted + inproc)
`browse_skills`	Skills	Yes	`skills`	Browse skill collections and search skills
`load_skill`	Skills	Yes	`skills`	Load a skill’s full instructions into the conversation
`skill_list_resources`	Skills	Yes	`skills`	List skill-owned resources
`skill_read_resource`	Skills	Yes	`skills`	Read a specific skill-owned resource
`skill_invoke_function`	Skills	Yes	`skills`	Invoke a skill-defined function
`tool_catalog_search`	Control plane	Yes	`builtins`	Search deferred tool-catalog entries
`tool_catalog_load`	Control plane	Yes	`builtins`	Load deferred tool-catalog entries into visibility
`meerkat_schedule_create`	Schedule	Yes	`schedule`	Create a new schedule
`meerkat_schedule_get`	Schedule	Yes	`schedule`	Read one schedule
`meerkat_schedule_list`	Schedule	Yes	`schedule`	List schedules
`meerkat_schedule_update`	Schedule	Yes	`schedule`	Update trigger, target, or policies
`meerkat_schedule_pause`	Schedule	Yes	`schedule`	Pause a schedule
`meerkat_schedule_resume`	Schedule	Yes	`schedule`	Resume a paused schedule
`meerkat_schedule_delete`	Schedule	Yes	`schedule`	Delete a schedule
`meerkat_schedule_occurrences`	Schedule	Yes	`schedule`	List occurrences for a schedule
`workgraph_create`	WorkGraph	No	`work_graph`	Create a work item
`workgraph_get`	WorkGraph	No	`work_graph`	Read one item
`workgraph_list`	WorkGraph	No	`work_graph`	List items
`workgraph_ready`	WorkGraph	No	`work_graph`	List ready items
`workgraph_snapshot`	WorkGraph	No	`work_graph`	Read an observability snapshot
`workgraph_events`	WorkGraph	No	`work_graph`	Read event history
`workgraph_claim`	WorkGraph	No	`work_graph`	Claim an item
`workgraph_release`	WorkGraph	No	`work_graph`	Release a claim
`workgraph_update`	WorkGraph	No	`work_graph`	Update item fields
`workgraph_block`	WorkGraph	No	`work_graph`	Mark an item blocked
`workgraph_close`	WorkGraph	No	`work_graph`	Close an item terminally
`workgraph_link`	WorkGraph	No	`work_graph`	Add an edge
`workgraph_add_evidence`	WorkGraph	No	`work_graph`	Add evidence
`workgraph_attention_reassign`	WorkGraph	No	`work_graph`	Reassign a WorkGraph attention binding
`workgraph_policy_escalate`	WorkGraph	No	`work_graph`	Monotonically tighten a WorkGraph completion policy

Enabling and disabling tools

Factory-level flags

AgentFactory controls which tool categories are available via builder methods:

Flag	Builder Method	Default	Controls
`enable_builtins`	`.builtins(bool)`	`false`	Task tools, utility tools (`datetime`, `apply_patch`, `view_image`), runtime-backed `generate_image`, and blob file tools when a blob store is wired
`enable_shell`	`.shell(bool)`	`false`	All shell tools (`shell`, `shell_jobs`, `shell_job_status`, `shell_job_cancel`)
`enable_memory`	`.memory(bool)`	`false`	`memory_search` (requires `memory-store-session` feature)
`enable_schedule`	`.schedule(bool)`	`false`	Scheduler tools (`meerkat_schedule_*`)
`enable_workgraph`	`.workgraph(bool)`	`false`	WorkGraph tools (`workgraph_*`)
`enable_comms`	`.comms(bool)`	`false`	All comms tools (requires `comms` feature)
`enable_mob`	`.mob(bool)`	`false`	Mob orchestration tools (`mob_`, `meerkat_`)

AgentFactory is the only place tool categories are composed. The public meerkat::AgentBuilder delegates to the factory path with explicit client/tool/store overrides. The lower-level meerkat_core::AgentBuilder is not re-exported by the facade and is not a public standalone embedding API. See AgentBuilder vs AgentFactory.Source: meerkat/src/factory.rs — AgentFactory struct and builder methods.

Per-build overrides

Each AgentBuildConfig can override factory-level flags for a single agent build:

Override Field	Type	Effect
`override_builtins`	`ToolCategoryOverride`	Explicit `enable`, `disable`, or `inherit`
`override_shell`	`ToolCategoryOverride`	Explicit `enable`, `disable`, or `inherit`
`override_memory`	`ToolCategoryOverride`	Explicit `enable`, `disable`, or `inherit`
`override_schedule`	`ToolCategoryOverride`	Explicit `enable`, `disable`, or `inherit`
`override_workgraph`	`ToolCategoryOverride`	Explicit `enable`, `disable`, or `inherit`
`override_mob`	`ToolCategoryOverride`	Explicit `enable`, `disable`, or `inherit`

All default to inherit (use the factory-level setting).Source: meerkat/src/factory.rs — AgentBuildConfig struct.

ToolPolicyLayer

Individual tools can be enabled or disabled via ToolPolicyLayer in BuiltinToolConfig. When shell is enabled, a ToolPolicyLayer is applied that activates the four shell tools (which have default_enabled: false).

Capability registrations

Capabilities are registered via the inventory crate in meerkat-tools/src/lib.rs:

Builtins (CapabilityId::Builtins): task_list, task_create, task_get, task_update, datetime, apply_patch, view_image, runtime-backed generate_image, and runtime-backed blob_save_file/blob_load_file/blob_inspect when a blob store is available. Controlled by config.tools.builtins_enabled.
Shell (CapabilityId::Shell): shell, shell_jobs, shell_job_status, shell_job_cancel. Controlled by config.tools.shell_enabled.
Schedule (CapabilityId::Schedule): meerkat_schedule_*. Controlled by config.tools.schedule_enabled.
WorkGraph (CapabilityId::WorkGraph): workgraph_*. Controlled by config.tools.workgraph_enabled.

Runtime tool scoping

Beyond static factory flags and per-build overrides, tool visibility can be changed at runtime during a live session. See Tool scoping for the conceptual overview.

ToolScope lifecycle

ToolScope (in meerkat-core) manages runtime tool visibility. It holds the base tool set from the dispatcher, an active external filter, and an optional per-turn overlay.Staging: External callers stage filter updates via ToolScopeHandle::stage_external_filter(filter). The staged filter is NOT applied immediately — the current turn is unaffected.Boundary apply: At the start of each CallingLlm loop iteration, tool_scope.apply_staged(dispatcher_tools) atomically promotes the staged filter to active, prunes stale tool names, and returns the visible tool set. A ToolConfigChanged event is emitted and a typed tool_config system notice is recorded in the conversation.Filter types:

ToolFilter::All — no restriction (default)
ToolFilter::Allow(set) — only listed tools are visible
ToolFilter::Deny(set) — listed tools are hidden

Composition: Most-restrictive wins. Multiple allow-lists intersect, multiple deny-lists union, deny beats allow.Persistence: The active external filter is stored in session metadata under tool_scope_external_filter and restored on session resume.Source: meerkat-core/src/tool_scope.rs

Live MCP server mutation

MCP servers can be added or removed from a running session. Operations are staged on the McpRouter and applied at the next turn boundary.

Surface	Method	Status
JSON-RPC	`mcp/add`, `mcp/remove`, `mcp/reload`	Fully wired (staged)
REST	`POST /sessions/{id}/mcp/add\|remove\|reload`	Fully wired
CLI	`rkat mcp add/remove/list/get`	Config surface; start or resume a session to load config
MCP server	`meerkat_mcp_add`, `meerkat_mcp_remove`, `meerkat_mcp_reload`	Fully wired

Servers being removed transition through Active → Removing (draining) → Removed to allow in-flight tool calls to complete before finalization.Source: meerkat-mcp/src/router.rs, meerkat-rpc/src/handlers/mcp.rs

Per-turn tool overlay

Mob flow steps can restrict tools for a single turn via TurnToolOverlay:

TurnToolOverlay {
    allowed_tools: Option<Vec<String>>,  // allow-list for this turn
    blocked_tools: Option<Vec<String>>,  // deny-list for this turn
}

Set on StartTurnRequest.turn_tool_overlay by the flow engine and other per-turn producers. Ephemeral — cleared after the turn completes. Composes with the external filter using most-restrictive semantics.Source: meerkat-core/src/service/mod.rs, meerkat-mob/src/runtime/flow.rs

Schedule tools

Schedule tools are the agent-facing scheduler surface. They are distinct from the host APIs (schedule/* over RPC and /schedules/* over REST).

Schedule tool inventory

Tool	Purpose
`meerkat_schedule_create`	Create a durable schedule with trigger, target, and policies
`meerkat_schedule_get`	Read one schedule by `schedule_id`
`meerkat_schedule_list`	List schedules in the active realm
`meerkat_schedule_update`	Update trigger, target, policies, or labels
`meerkat_schedule_pause`	Pause a schedule
`meerkat_schedule_resume`	Resume a paused schedule
`meerkat_schedule_delete`	Delete a schedule
`meerkat_schedule_occurrences`	List occurrences for a schedule

These tools are provided by ScheduleToolDispatcher in meerkat-schedule and are gated by the scheduler capability.

WorkGraph tools

WorkGraph tools are the agent-facing write path for durable work. Host RPC, REST, and CLI expose observability; CLI and trusted hosts add narrow goal and attention controls.

WorkGraph tool inventory

Tool	Purpose
`workgraph_create`	Create a durable work item
`workgraph_get`	Read one item
`workgraph_list`	List items with filters
`workgraph_ready`	List machine-derived ready items
`workgraph_snapshot`	Read items, edges, ready ids, timestamp, and event high-water mark
`workgraph_events`	Read event history
`workgraph_claim`	Claim an item with expected revision and typed owner
`workgraph_release`	Release an active claim
`workgraph_update`	Update mutable fields
`workgraph_block`	Mark an item blocked
`workgraph_close`	Close as `completed`, `cancelled`, or `failed`
`workgraph_link`	Add an edge
`workgraph_add_evidence`	Add an evidence reference
`workgraph_attention_reassign`	Reassign an attention binding with a current authority projection
`workgraph_policy_escalate`	Monotonically tighten an item’s completion policy

For operating guidance, load the workgraph-workflow companion skill when it is available. For the data model and host observability surfaces, see WorkGraph reference.

Task tools

Task tools provide structured work tracking. They are enabled by default when builtins are on. Tasks are persisted via TaskStore (either FileTaskStore on disk or MemoryTaskStore in-memory).

Task data model

A Task object returned by task tools has these fields:

Field	Type	Description
`id`	`String`	Unique task identifier
`subject`	`String`	Short subject/title
`description`	`String`	Detailed description
`status`	`String`	`"pending"`, `"in_progress"`, or `"completed"`
`priority`	`String`	`"low"`, `"medium"`, or `"high"`
`labels`	`String[]`	Labels/tags for categorization
`blocks`	`String[]`	IDs of tasks that this task blocks
`blocked_by`	`String[]`	IDs of tasks that block this task
`created_at`	`String`	ISO 8601 creation timestamp
`updated_at`	`String`	ISO 8601 last-updated timestamp
`created_by_session`	`String?`	Session ID that created this task
`updated_by_session`	`String?`	Session ID that last updated this task
`owner`	`String?`	Owner/assignee (agent name or user identifier)
`metadata`	`Object`	Arbitrary key-value metadata

Source: meerkat-tools/src/builtin/types.rs — Task struct.

task_create

Create a new task in the project task list.Default enabled: Yes

String

required

Short subject/title of the task.

String

required

Detailed description of what needs to be done.

String

default:"medium"

"low", "medium", or "high".

String[]

default:"[]"

Labels/tags for categorization.

String[]

default:"[]"

Task IDs that this task blocks.

String[]

default:"[]"

Task IDs that block this task.

String

default:"null"

Owner/assignee.

Object

default:"{}"

Arbitrary key-value metadata.

Returns: The created Task object (see task data model above).Source: meerkat-tools/src/builtin/tasks/task_create.rs

task_get

Get a task by its ID.Default enabled: Yes

String

required

The task ID to retrieve.

Returns: The Task object matching the given ID.Error: ExecutionFailed if the task ID is not found.Source: meerkat-tools/src/builtin/tasks/task_get.rs

task_list

List tasks in the project, optionally filtered by status or labels.Default enabled: Yes

String

default:"null (all)"

Filter by status: "pending", "in_progress", or "completed".

String[]

default:"null (all)"

Filter by labels (tasks matching any label).

Returns: Array of Task objects matching the filters.Source: meerkat-tools/src/builtin/tasks/task_list.rs

task_update

Update an existing task. Only provided fields are modified; omitted fields remain unchanged.Default enabled: Yes

String

required

The task ID to update.

String

default:"unchanged"

New subject/title.

String

default:"unchanged"

New description.

String

default:"unchanged"

New status: "pending", "in_progress", or "completed".

String

default:"unchanged"

New priority: "low", "medium", or "high".

String[]

default:"unchanged"

Replace all labels.

String

default:"unchanged"

New owner/assignee.

Object

default:"unchanged"

Merge metadata (set key to null to remove).

String[]

default:"[]"

Task IDs to add to the blocks list.

String[]

default:"[]"

Task IDs to remove from the blocks list.

String[]

default:"[]"

Task IDs to add to the blocked_by list.

String[]

default:"[]"

Task IDs to remove from the blocked_by list.

Returns: The updated Task object.Error: ExecutionFailed if the task ID is not found.Source: meerkat-tools/src/builtin/tasks/task_update.rs

Shell tools

Shell tools execute commands and manage background jobs. They are all default_enabled: false and require the factory-level enable_shell flag (or a ToolPolicyLayer override) to be active.

background: true is available only when the session has a persistent realm job store and blob store. Submission, status, result references, cancellation, and terminal delivery are durable. The shell worker itself is non_resumable: if its process is lost across restart, the committed attempt becomes worker_lost after its existing lease expires and is never silently replayed.

command: "some-command &" and background: true are different contracts. An ampersand is only syntax interpreted by the selected shell. Meerkat still executes that shell invocation through the foreground tool path, returns the ordinary foreground result, and does not create a job ID or a record visible to shell_jobs, shell_job_status, or shell_job_cancel. Any child the shell leaves running is unmanaged and its lifetime is not guaranteed. Use background: true when the command must be managed as a Meerkat shell job. It commits and returns a stable job ID and enables durable status/list/cancel operations. This does not claim that the subprocess survives a host restart: the durable record survives and reports the non-resumable worker loss.

Timeout hierarchy

Tool execution has layered deadlines; the narrowest applicable layer wins.

Layer	Default/current contract	Meaning
Foreground shell command	30 seconds	Shell-internal command deadline
SDK/builder `ToolDispatcher`	30 seconds	Enforced dispatcher-layer deadline when this wrapper is composed
Schedule occurrence lease	60 seconds	Scheduling/redelivery ownership lease; not a long-job execution deadline
Normal Meerkat tool batch	600 seconds	Agent-loop outer deadline; per-tool overrides may narrow it
MobKit provider callback	120 seconds	Public host-callback work window
MobKit Python/TypeScript callback cancellation	125 seconds	Host cancellation margin, not extra work time
MobKit gateway callback wire	130 seconds	Transport margin, not extra work time
LLM stream inactivity	300 seconds	Provider-stream watchdog; unrelated to tool callbacks

Changing the normal Meerkat tool timeout cannot extend a narrower shell, SDK/builder ToolDispatcher, or MobKit callback deadline. The foreground shell and dispatcher deadlines are distinct enforced layers, even though both defaults currently come from ToolTimeoutPolicy. Background shell submission returns within the normal tool call, but the spawned command keeps its own shell timeout. The command runs under one fenced non-resumable attempt; terminal state is committed before runtime notification delivery.

Shell configuration

Shell behavior is controlled by ShellConfig:

Config Field	Type	Default	Description
`enabled`	`bool`	`false`	Master switch for shell tools
`default_timeout_secs`	`u64`	`30`	Default command timeout
`restrict_to_project`	`bool`	`true`	Restrict working dirs to project root
`shell`	`String`	`"nu"`	Shell binary name (Nushell by default; falls back to bash/zsh/sh)
`shell_path`	`PathBuf?`	`None`	Explicit shell binary path
`project_root`	`PathBuf`	CWD	Project root for path restriction
`max_completed_jobs`	`usize`	`100`	Maximum completed jobs retained
`completed_job_ttl_secs`	`u64`	`300`	TTL for completed job records (seconds)
`max_concurrent_processes`	`usize`	`10`	Maximum concurrent background processes
`security_mode`	`SecurityMode`	`Unrestricted`	Command security policy
`security_patterns`	`Vec<String>`	`[]`	Glob patterns for allow/deny lists

Source: meerkat-tools/src/builtin/shell/config.rs

Shell security modes

The SecurityEngine validates commands before execution using POSIX-compliant word splitting (shlex) and glob pattern matching (globset).

Mode	Behavior
`Unrestricted`	All commands allowed (default)
`AllowList`	Only commands matching `security_patterns` globs are allowed
`DenyList`	Commands matching `security_patterns` globs are rejected

Patterns are matched against the canonicalized command invocation. The engine parses the full command string into individual words, then validates the executable (first word) and the full command string against the pattern set.Source: meerkat-tools/src/builtin/shell/security.rs

shell

Execute a shell command. Uses POSIX-style parsing for policy checks; runs via Nushell or fallback shell.Default enabled: No (requires shell to be enabled)

String

required

The command to execute (POSIX-style parsing for policy checks).

String

default:"Project root"

Working directory (relative to project root).

u64

default:"Config default (30)"

Timeout in seconds.

bool

default:"false"

If true, durably submit a non-resumable shell job and return its stable job ID. Requires persistent realm job and blob stores. Job truth survives restart; a lost subprocess is classified as worker_lost, not replayed.

{
  "exit_code": 0,
  "stdout": "...",
  "stderr": "...",
  "timed_out": false,
  "duration_secs": 1.23
}

{
  "job_id": "job_<uuid-v7>",
  "status": "running",
  "message": "Background job started"
}

Output is truncated to the last 100,000 characters if it exceeds that limit. Fields stdout_lossy and stderr_lossy indicate whether output was lossy-decoded from non-UTF-8 bytes.

Source: meerkat-tools/src/builtin/shell/tool.rs

shell_jobs

List all background shell jobs.Default enabled: No (requires shell to be enabled)Parameters: None (empty object).

[
  {
    "id": "job_<uuid-v7>",
    "command": "echo hello",
    "status": "running",
    "started_at_unix": 1700000000
  }
]

The status field is one of: "running", "completed", "failed", "timed_out", "cancelled".Source: meerkat-tools/src/builtin/shell/jobs_list_tool.rs

shell_job_status

Check status of a background shell job. Returns full job details including output when complete.Default enabled: No (requires shell to be enabled)

String

required

The job ID to check.

{
  "id": "job_<uuid-v7>",
  "command": "echo test",
  "working_dir": "/path/to/project",
  "timeout_secs": 30,
  "started_at_unix": 1700000000,
  "status": "completed"
}

Error: ExecutionFailed if the job ID is not found.Source: meerkat-tools/src/builtin/shell/job_status_tool.rs

shell_job_cancel

Request cancellation of a running background shell job. For a live process, success returns cancellation_requested; this is not a terminal acknowledgement. Poll shell_job_status until it reports cancelled. Meerkat publishes terminal cancelled status only after the worker proves the complete process group has been contained. Synthetic jobs with no live process may return cancelled immediately because there is nothing to contain.Default enabled: No (requires shell to be enabled)

String

required

The job ID to cancel.

{
  "job_id": "job_<uuid-v7>",
  "status": "cancellation_requested"
}

Error: ExecutionFailed if the job ID is not found.Source: meerkat-tools/src/builtin/shell/job_cancel_tool.rs

Shell types

JobId format: "job_" followed by a UUID v7 string.JobStatus variants: Running, Completed, Failed, TimedOut, Cancelled (serialized as lowercase snake_case strings).Source: meerkat-tools/src/builtin/shell/types.rs

Memory tool

The memory search tool lives in the meerkat-memory crate and is composed into the tool dispatcher as a separate MemorySearchDispatcher (implementing AgentToolDispatcher). It is NOT part of CompositeDispatcher — it is wired via ToolGateway when the memory-store-session feature is enabled and enable_memory is true.

memory_search

Search semantic memory for past conversation content. Memory contains text from earlier turns in the current session that were compacted away to save context space.

String

required

Natural language search query describing what you want to recall.

usize

default:"5"

Maximum number of results to return (max: 20).

The limit is capped at 20 regardless of the requested value.

[
  {
    "content": "The project codename is AURORA-7",
    "score": 0.87,
    "source_range": { "start": 3, "end": 4 }
  }
]

source_range is the half-open [start, end) offset range of the source message(s) the entry was indexed from. Memory is scoped to a single session; results do not carry a session_id, and there is no cross-session recall.Returns an empty array if no matches are found.Source: meerkat-memory/src/tool.rs

Utility tools

Utility tools are general-purpose helpers enabled by default when builtins are on.

datetime

Get the current date and time. Returns ISO 8601 formatted datetime and Unix timestamp.Default enabled: YesParameters: None (empty object).

{
  "iso8601": "2025-01-15T14:30:00+01:00",
  "date": "2025-01-15",
  "time": "14:30:00",
  "timezone": "+01:00",
  "unix_timestamp": 1736949000,
  "year": 2025,
  "month": 1,
  "day": 15,
  "weekday": "Wednesday"
}

Source: meerkat-tools/src/builtin/utility/datetime.rs

view_image

Read an image file from the project directory and return its contents as a base64-encoded ContentBlock::Image. This enables vision-capable models to analyze images from disk during tool use.Default enabled: Yes (when builtins are on and the model supports image tool results)

String

required

Path to the image file, relative to the project root.

Supported formats: PNG, JPEG, GIF, WebP, SVG.Size limit: 5 MB. Files exceeding this limit return an error.Capability gating: view_image is currently hidden via ToolScope when the active model does not support image content in tool results (ModelProfile.image_tool_results == false).Returns: A content-block result containing a single ContentBlock::Image with the base64-encoded image data and detected media type.Source: meerkat-tools/src/builtin/utility/view_image.rs

blob_save_file

Save decoded bytes from the session blob store to a file inside the project root. This is the model-facing equivalent of materializing a blob with rkat blob get, but it remains sandboxed to the active project.Default enabled: Yes when builtins are on and the runtime-backed session has a blob store.

String

required

Blob ID to save.

String

required

Destination path, relative to the project root or absolute within the project root.

Boolean

default:"false"

Whether to replace an existing file.

Returns: JSON metadata: blob_id, media_type, path, and bytes_written. Raw bytes are never returned in the tool result.Source: meerkat-tools/src/builtin/utility/blob_file.rs

blob_load_file

Read a file inside the project root and store its bytes in the realm blob store.Default enabled: Yes when builtins are on and the runtime-backed session has a blob store.

String

required

Source path, relative to the project root or absolute within the project root.

String

default:"inferred from extension"

Optional media type. When omitted, Meerkat infers common image, text, JSON, CSV, SVG, and PDF media types from the file extension.

Size limit: 25 MB.Returns: JSON metadata: blob_id, media_type, path, and bytes_read. Raw bytes are never returned in the tool result.Source: meerkat-tools/src/builtin/utility/blob_file.rs

blob_inspect

Inspect a blob without returning its raw payload.Default enabled: Yes when builtins are on and the runtime-backed session has a blob store.

String

required

Blob ID to inspect.

Returns: JSON metadata: blob_id, media_type, and decoded size_bytes.Source: meerkat-tools/src/builtin/utility/blob_file.rs

generate_image

Generate or edit an assistant-owned image through the session image-generation substrate. Generated bytes are committed to the realm blob store and returned as durable AssistantImageRef values.Default enabled: Yes when builtins are on and the runtime-backed session has image-generation machine, executor, planner, and blob-store wiring.

Object

required

Image generation request. The simple shape supports intent, prompt, instruction, source_images, reference_images, size, quality, format, count/n, target, provider, model, and provider_params.

Common request:

{
  "request": {
    "intent": "generate",
    "prompt": "a cozy tabby cat by a sunlit window",
    "size": "1024x1024",
    "quality": "auto",
    "format": "png",
    "count": 1,
    "provider": "openai"
  }
}

Targets: auto uses the current provider’s image profile when available. Use provider: "openai" or provider: "gemini" to force a provider default. Use provider plus model to force a provider-owned image model.Supported universal options: size accepts auto, 1024x1024, 1024x1536, 1536x1024, or WIDTHxHEIGHT; quality accepts auto, low, medium, high; format accepts auto, png, jpeg, jpg, webp; count is currently limited to 1.Provider params: Use top-level size, quality, format, and intent for normal requests; these are Meerkat fields, not raw provider params. For the current gpt-image-2 default, OpenAI provider_params should normally be limited to background, output_compression, moderation, hosted-tool-only action, hosted-tool-only reasoning_effort, and hosted-tool-only web_search; background is auto or opaque only, output_compression applies when format is jpeg/webp, moderation is auto or low, action is usually omitted in favor of top-level intent, and input_fidelity is not accepted by Meerkat. Gemini accepts aspect_ratio and image_size.Returns: ImageGenerationToolResult JSON containing operation_id, terminal, images, provider_text, revised_prompt, native_metadata, and warnings. Each generated image includes blob_ref.blob_id, which can be saved from inside the session with blob_save_file or fetched externally with rkat blob get <blob_id> --output image.png.Source: meerkat-tools/src/builtin/image_generation.rsSee Image generation for provider behavior, examples, and troubleshooting.

Comms tools

Comms tools enable inter-agent communication. They require the comms Cargo feature (dep:meerkat-comms) and the factory-level enable_comms flag. Unlike other tool categories, comms tools are provided as a separate CommsToolSurface dispatcher (implementing AgentToolDispatcher) and composed via DynamicToolComposite, NOT bundled into CompositeDispatcher. Tool availability is reported per tool through the catalog (comms_tool_unavailable_reason): send_message and peers are advertised even before any peers are configured, while send_request and send_response require a runtime-bound command authority and are otherwise marked unavailable with the typed reason RuntimeCommandAuthorityUnavailable. Tool definitions (name, description, input schema) are dynamically loaded from meerkat_comms::tools_list().

send_message

Send a fire-and-forget collaboration message to a trusted peer.Default enabled: Yes (when comms is active)

String

required

Canonical peer ID from the peers tool.

String

Optional display name, retained only for diagnostics.

String

required

Message content.

Array

Optional multimodal blocks: text entries or image_ref entries (source: "current_turn" with index, or source: "blob" with blob_id and media_type).

String

required

Use "queue" for ordinary delivery or "steer" for immediate steer processing on runtime-backed sessions.

{ "status": "sent", "kind": "peer_message", "receipt": { ... } }

Source: meerkat-comms/src/mcp/tools.rs

send_request

Send a structured request to a trusted peer. Use when you want explicit intent + params and a correlated response via send_response. Requires a runtime-bound command authority.Default enabled: Yes (when comms is active and runtime command authority is attached)

String

required

Canonical peer ID from the peers tool.

String

Optional display name, retained only for diagnostics.

String

required

Typed request intent: "checksum_token" or "supervisor.bridge". Unknown intents fail at the serde boundary.

Object

required

Request parameters, validated against the selected intent.

Array

Optional multimodal blocks (text and image_ref entries).

String

required

Use "queue" for ordinary delivery or "steer" for immediate steer processing on runtime-backed sessions.

Use send_message for normal agent collaboration. Use send_request only when you want an explicit structured ask and later send_response correlated by in_reply_to.

{ "status": "sent", "kind": "peer_request", "receipt": { ... } }

Source: meerkat-comms/src/mcp/tools.rs

send_response

Send a response to a previously received request from a trusted peer. Requires a runtime-bound command authority.Default enabled: Yes (when comms is active and runtime command authority is attached)

String

required

Canonical peer ID from the peers tool.

String

Optional display name, retained only for diagnostics.

String (UUID)

required

ID of the request being responded to.

String

required

Response status: "accepted", "completed", or "failed".

Object

default:"null"

Typed response payload, validated against the original request contract.

Array

Optional multimodal blocks (text and image_ref entries).

String

Optional override for terminal responses: "queue" or "steer". Forbidden on "accepted" progress responses.

{ "status": "sent", "kind": "peer_response", "receipt": { ... } }

Source: meerkat-comms/src/mcp/tools.rs

peers

List all visible peers with connection info and optional metadata.Returns entries from the TrustStore (keyed by canonical PeerId), excluding the current agent (“self”) by public key. Names are display labels and may not be unique — use peer_id for sends.Default enabled: Yes (when comms is active)Parameters: None (empty object).

{
  "peers": [
    {
      "name": "agent-beta",
      "peer_id": "0193a1b2-...",
      "address": "tcp://127.0.0.1:4200"
    }
  ]
}

Source: meerkat-comms/src/mcp/tools.rs — PeersInput

Cargo feature gates

Tool availability depends on compile-time features in the meerkat-tools crate:

Feature	Default	Dependencies	Tools unlocked
`comms`	Yes	`dep:meerkat-comms`	`send_message`, `send_request`, `send_response`, `peers`
`mcp`	Yes	`dep:meerkat-mcp`	External MCP tool routing (not builtin tools)

The memory_search tool is gated by the memory-store-session feature on the meerkat facade crate (not meerkat-tools), since MemorySearchDispatcher lives in meerkat-memory. Source: meerkat-tools/Cargo.toml

Reference

Architecture

Operations

Built-in tools reference

Overview

Enabling and disabling tools

Runtime tool scoping

Schedule tools

WorkGraph tools

Task tools

Shell tools

Timeout hierarchy

Memory tool

Utility tools

Comms tools

Cargo feature gates

​Overview

​Enabling and disabling tools

​Runtime tool scoping

​Schedule tools

​WorkGraph tools

​Task tools

​Shell tools

​Timeout hierarchy

​Memory tool

​Utility tools

​Comms tools

​Cargo feature gates

Overview

Enabling and disabling tools

Runtime tool scoping

Schedule tools

WorkGraph tools

Task tools

Shell tools

Timeout hierarchy

Memory tool

Utility tools

Comms tools

Cargo feature gates