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

Beyond annotations (readOnlyHint, idempotentHint, destructiveHint), description adds that unknown ids and others' ids both return found:false by design, and lists returned fields (status, goal, tickers, etc.). No contradiction with annotations.

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?

Description is four sentences, well-organized: main purpose first, then details on scope, return info, and design note. Slightly verbose but efficient.

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 simple read tool with one parameter and existing output schema, description covers input source, returned fields, error behavior, and access tier. No significant gaps.

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?

Only one parameter (run_id) with 100% schema coverage. Description in tool repeats schema's description ('from list_agent_runs'). Adds no new constraint beyond schema, so baseline 3 is appropriate.

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?

Clearly states 'Fetch full detail for one of the caller's own standing-agent runs by id', specifying verb (fetch), resource (agent runs), and source of id. Distinguishes from sibling 'list_agent_runs' by focusing on single-run detail.

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?

Tells agent id comes from list_agent_runs and explains behavior for unknown/inaccessible ids ('returns found: false'). Mentions tier restriction. Doesn't explicitly say when not to use or list alternatives, but context is clear and helpful.

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