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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds non-obvious behavior: 'IMDb may return fewer rows than total; check has_more for incomplete page coverage,' which is a real pagination caveat an agent needs. It adds useful context beyond the structured fields.

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?

Four sentences, front-loaded with the core purpose, then the input constraint, then the pagination caveat, then the sibling alternative. Each sentence carries distinct information with no filler, though the alternative-sentence could arguably live as a routing note elsewhere.

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 values need not be spelled out, and the description correctly focuses on inputs, the partial-results caveat, and the sibling alternative. For a single-title keyword fetcher, this is essentially complete; no significant gap remains.

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 two parameters are individually documented and the baseline is 3. The description adds meaning the schema does not enforce: exactly one of id/url must be supplied (mutual exclusivity) and the id format is '(tt...)'. This is meaningful beyond the schema text.

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 ('Fetch') and resource (IMDb plot-keyword rows plus keyword-search URLs) for a title, which cleanly distinguishes it from the ~20 other imdb_title_* siblings that fetch different resources. An agent can identify this as the keywords tool without opening the 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?

Explicitly routes away from a sibling: 'Use imdb_title_similar for recommended titles rather than descriptive keyword tags.' It also gives the input constraint 'Pass exactly one title id or title URL.' It stops short of stating positive when-to-use conditions, but the alternative and constraint are clear.

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