Assign a task to a specific agent by ID, or unassign it by passing null. Use to delegate work and track agent ownership.
Assign a task to an agent (or unassign by passing null)
| Name | Required | Description | Default |
|---|---|---|---|
| task_id | Yes | The task ID to assign | |
| agent_id | Yes | Agent ID to assign the task to, or null to unassign |
Changes observed during successful MCP inspections.
v1.19.0Input schema / properties / agent_id / anyOfRemoved value: -[
- {
- "type": "string"
- },
- {
- "type": "number"
- },
- {
- "type": "null"
- }
-]Input schema / properties / agent_id / typeAdded value: +[
+ "string",
+ "number",
+ "null"
+]Input schema / properties / task_id / anyOfRemoved value: -[
- {
- "type": "string"
- },
- {
- "type": "number"
- }
-]Input schema / properties / task_id / typeAdded value: +[
+ "string",
+ "number"
+]v1.2.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations present, the description carries the full behavioral burden, yet it discloses almost nothing: not whether assignment overwrites an existing agent, whether permissions are required, whether the target agent is notified, or whether the operation is reversible. Only the mutation/unassign duality is conveyed.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single tight sentence that front-loads the core action and appends the reversal case. No filler or redundancy.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a two-parameter mutation tool with no annotations and no output schema, the definition is minimally adequate: it names the action and the unassign path but omits side effects, permissions, and reassignment semantics that an agent would need to invoke it confidently.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% and both parameters are documented in the schema, including the null-to-unassign semantics for agent_id. The description restates that same null behavior rather than adding format, type, or constraint detail, so baseline 3 applies.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
It states a specific verb (assign) and resource (task to an agent) and even covers the inverse operation (unassign via null). However, it offers no differentiation from closely related siblings such as claim_task, delegate_task, or release_task, so an agent must infer which assignment path applies.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The only usage hint is the parenthetical about passing null to unassign, which is really parameter behavior. There is no statement of when to prefer this over claim_task or delegate_task, nor any prerequisite or context for invoking it.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.