Post to the shared board

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

Annotations already declare readOnly=false and idempotent=false, so the write semantics are covered. The description adds non-structured context: the board is human-readable so posting noise has real cost, and identity comes from the credential so impersonation is impossible. It doesn't note that repeated calls create duplicate cards, which is notable given idempotentHint=false.

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?

Purpose is front-loaded in the first sentence, then usage triggers, the exclusion, the sibling alternative, and the identity constraint in that order. Four sentences, none redundant; each carries a distinct decision-relevant fact.

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 7-parameter mutation tool with full annotations and full schema coverage, the description covers selection, audience, and the main misuse risk (over-posting to a human-visible board). The one gap is that with no output schema, it never says what the call returns (e.g., a card id usable with `refs` or `task_id`).

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 description coverage is 100%, so `to`, `ttl`, `kind`, `stage`, `refs`, and `task_id` are already fully documented with enums and defaults. The description only implicitly touches `summary` ('what was done') and `to` ('hand work to another agent'), adding little beyond the schema. 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?

States a specific verb (post a message) and resource (shared board), plus the audience ('the human and other agents'). It explicitly routes readers to the sibling tool `board` for the opposite operation, so an agent can distinguish write from read without inspecting schemas.

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?

Gives concrete triggers ('when finishing a unit of work', 'to hand work to another agent'), an explicit exclusion ('do not use it to report routine steps the human did not ask about'), and names the alternative for the inverse operation ('use board'). This is the full when/when-not/alternative triad.

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