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

Annotations already signal read-only, idempotent, non-destructive behavior voice; the description goes well beyond by explaining status semantics, poll_after_seconds, progress, eta_seconds, film_check advice, notices behavior, caption handling, and posts[] after post_run. This is rich behavioral context that structured fields 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?

The description is long but front-loaded with the core purpose and immediate polling guidance. Every sentence adds useful operational detail rather than filler. The density and single-paragraph structure make it slightly harder to scan, so it earns a 4 rather than a 5.

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?

Given the tool's complexity and the presence of an output schema, the description thoroughly covers polling behavior, terminal status, field semantics, human-decision advice, re-render constraints, notices, captions, and post-run posts data. Nothing critical 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?

The input schema already covers the single parameter with 100% coverage and specifies that run_id comes from create_campaign, render_asset, or list_runs. The description reinforces this context but does not add new parameter-level meaning beyond what the schema provides, so the baseline of 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?

The description opens with a specific verb+resource: 'Get one run by id', followed by a concrete list of what is returned (status, output text, asset URLs, caption, error). This clearly differentiates it from list_runs and other sibling tools.

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?

It gives explicit when-to-use guidance: poll after create_campaign or render_asset until status is terminal, and wait poll_after_seconds between polls. It doesn't explicitly state when not to use it or name an alternative tool, so it stops short of a full 5.

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