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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description does add domain semantics beyond that — 'hold' explicitly includes a 'stale claim', and the second return element is explained as an agent stamped on the pull request — but says nothing about what counts as stale, what is returned when nobody holds it, or any auth requirements.

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 dense sentence with the primary answer (who holds it) front-loaded and the secondary answer in a clarifying parenthetical. Nothing is wasted, though the parenthetical is slightly compressed to the point of being cryptic on first read.

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?

With no output schema, the description must carry return semantics, and it only partially does: it names the two facts returned but not their shape (holder identity, claim age, timestamps, empty-state behavior). For a two-parameter read-only lookup this is adequate but leaves the agent guessing at the response format.

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%, with the repo parameter well documented ('Optional when the token covers one repository') and issue constrained to 1-9999999. The description only echoes the issue number as '#N' and never touches the optional repo fallback, so it adds nothing the schema does not already carry.

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 query ('whether anyone holds issue #N') plus the secondary datum it returns ('who last worked on it'), which is far more informative than the title's 'Who holds an issue'. It is clearly distinct from the sibling set (needs_you, live_sessions, almost_done), though it never explicitly contrasts itself with any of them.

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?

There is no when-to-use instruction, no prerequisite, and no named alternative. The use case (checking claim status before picking up an issue) is only inferable from the phrasing, not stated, so the agent must guess at the trigger condition.

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