Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description directly contradicts the annotations: it claims 'Idempotent: if the user is already assigned, returns the existing assignment without error,' while `idempotentHint` is false in the annotations. This is an annotation contradiction and severely undermines trust in the tool's behavioral disclosure.

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?

The description is two sentences, starts with the primary action, and every clause adds useful information: the action, idempotency, and a business rule. There is no filler or repetition.

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 mutation tool with two required parameters, no output schema, and incomplete annotations, the description provides key context (idempotency, company constraint) but misses a clear explanation of the response/return value and does not resolve the idempotency contradiction. It is adequate but not complete.

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?

The schema description coverage is 0% per context, and the tool description does not compensate by explaining the parameters beyond the action. It adds the company-membership constraint for `user_id` content, but it does not clarify the `kwargs`/`body` nesting or the parameter roles beyond what the schema already states. For nested required parameters, more semantic guidance is needed.

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?

The description uses a specific verb ('Adds') and resource ('a user as an assignee on a task'), making the action immediately clear. It also distinguishes itself from the sibling `unassign_user_tasks` by naming the assignment direction, and the idempotency note further disambiguates behavior.

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 description gives a clear context for when to invoke the tool: assigning a user to a task, and it states a concrete prerequisite (the user must belong to the same company as the task's project). It does not explicitly mention alternative tools or when not to use it, but the sibling list makes the main contrast obvious via `unassign_user_tasks`.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.