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

Goes well beyond the annotations by disclosing real side effects: a history line, watcher notices issued in the caller's name, and that concurrent description edits are not lost. It also documents idempotency ('Ticking a ticked item changes nothing') and the failure semantics for unknown ids, which annotations like destructiveHint cannot convey.

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?

Front-loads the action and the id source in the first clause, then layers side effects, idempotency, and error handling in a tight sequence. Dense but each sentence carries distinct operational information; only the em-dash aside on concurrent edits is slightly ornate.

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?

Covers action, identifier source, permissions, side effects, idempotency, stale-id recovery, and the 'changed' false return value, which substitutes for the absent output schema. Nothing an agent needs to invoke it correctly is missing.

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%, so the baseline is 3, but the description adds meaning the schema does not: the id's provenance and lifecycle (rewritten or removed items make ids stale) and the no-op behavior when 'checked' matches current state.

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 pair (tick/untick), the exact resource (one checklist item), and the identifier source ('id' from get_checklist). An agent can distinguish this from get_checklist and from issue-editing tools without opening any 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 clear preconditions ('Requires permission to edit the issue') and a recovery path when the id is stale ('read the checklist again'). It does not name an explicit alternative tool or a when-not-to-use case, but the operation is narrow enough that few exist.

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