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

Adds meaning beyond the annotations: it discloses the downstream effect that 'from the next morning's check, briefing and trend show what changed since,' which no structured field conveys. It also restates reversibility with the concrete `undo: true` mechanism, useful even though destructiveHint=false already signals safety. Idempotency is covered only by the annotation, not reinforced in prose.

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?

Four short sentences, front-loaded with what happens and the core trigger, with reversibility and sibling differentiation following. Every sentence carries information an agent needs; nothing is filler.

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 this is complete: annotations cover the safety profile, the schema fully documents all four parameters, an output schema exists, and the description still adds the downstream consequence and the undo path. An agent has everything needed to call it correctly and to reverse a bad call.

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% and all four parameters carry their own descriptions, so the baseline is 3. The description adds only the optionality of the URL; it does not explain `move` id-vs-rank formats or `site` fallback behavior beyond what the schema already documents.

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 and resource ('Records that a move has shipped') and pins down the payload (today's date, optional URL). It also explicitly distinguishes itself from all siblings with 'The only tool that writes,' so an agent can classify it without opening the schema.

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 an explicit trigger: 'Use it after the person (or their coding session) has shipped the move,' and points to `undo: true` as the correction path. It never states the negative case directly (e.g. do not call before shipping) nor names which sibling to use instead for pre-shipment actions, so it stops short of full when/when-not coverage.

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