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

Adds real behavior beyond the readOnlyHint/openWorldHint annotations: unavailable sections appear in missing_sections with partial=true, and only failure of every section yields an error. This partial-success semantics is exactly the kind of non-obvious behavior an agent needs. It stops short of noting rate limits or cost of the aggregate fetch.

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?

Three tight sentences: what it does, the failure/partial contract, and the sibling routing pointer. The most actionable constraint (check partial) is placed before the alternative pointer, and nothing is redundant.

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?

An output schema exists, so return-value detail is unnecessary; the description covers the one thing the schema cannot — the partial_sections contract and the all-sections-failed error condition. Combined with the annotations and sibling pointer, an agent has everything needed to call it correctly.

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?

Both parameters (id, url) are fully documented in the schema at 100% coverage, so the schema does the heavy lifting. The description only restates 'one title id or URL' without adding format guidance (e.g., which wins if both are supplied, or the accepted URL shape) beyond what the schema already says.

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 (summarize) plus the exact resource and the enumerated sections it aggregates (trivia, goofs, quotes, keywords, filming locations, company credits). This clearly distinguishes it from the many per-section siblings like imdb_title_trivia or imdb_title_goofs, which fetch one section each.

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?

Explicitly routes to imdb_title for title metadata, and instructs the agent to check partial before treating the result as complete. It gives clear usage context but does not state when-not-to-use this aggregator (e.g., prefer a per-section sibling when you only need one section).

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