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

Annotations already mark it read-only, idempotent, and non-destructive. The description adds meaningful behavioral context: credit cost, slug-to-id resolution cost behavior, and that data.activities[].entityId feeds /posts/info, /posts/comments, /posts/likes. 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?

Three terse sentences, front-loaded with what the tool returns and immediately useful resolution/cost details. Each sentence earns its place, though the second sentence is dense with endpoint names.

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?

Together with output schema, annotations, and parameter descriptions, the tool definition covers return consumption, identifier formats, pagination (via start), and cost. It could be more explicit about default behavior when neither id nor slug is supplied, but the overall package is sufficient.

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?

Input schema covers 100% of parameters in detail; the description repeats the id/slug resolution guidance already present in the schema and adds only the credit-cost note. That is not enough to raise above the schema-covered baseline.

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 opening phrase and annotation title identify the resource and action ('recent posts' / 'List company posts'), and the mention of data.activities[].entityId links returned records to downstream post endpoints. It does not explicitly name sibling tools like posts_all or companies_info, so differentiation rests on 'company's recent posts' rather than an explicit contrast.

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?

The description gives concrete invocation context: pass slug (auto-resolved at no extra credit cost) or pass id from companies_entity_id to skip lookup, plus the 10-credit cost. It does not, however, state when to prefer this over alternatives such as posts_all, posts_info, or companies_entity_id, nor any exclusions.

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