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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so safety is covered. The description adds value beyond them by disclosing cost ('10 points per returned record') and by indicating what payload each result type carries (page contacts, followers, rating vs. post text and engagement).

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?

A single dense sentence covers scope, options, output fields and cost with no filler. It front-loads the core action, though the trailing clause about contacts/followers/rating is somewhat compressed and slows parsing.

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 read-only search tool with no output schema, 4 fully documented parameters and complete annotations, the description supplies the missing pieces an agent needs: what each search type returns and the per-record cost. Only the absence of sibling routing guidance keeps it from being complete.

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 baseline is 3; the description goes further by pairing result types with the fields they yield, which helps the agent pick a search_type for a data need. It does not explain location filtering semantics or max_items pricing interplay, but the added meaning is real.

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 and resource ('Search Facebook by keyword') and enumerates the entity types returned: pages, profiles, posts, reels. It does not differentiate itself from close siblings like run_facebook_pages or run_facebook_posts, so an agent cannot tell whether to use keyword search or a direct-lookup tool from the description alone.

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?

Usage is implied by 'by keyword' and the optional location, and search_type hints at the different modes. But there is no explicit statement of when to prefer this over run_facebook_pages/run_facebook_posts/run_facebook_groups, nor any exclusion or prerequisite guidance.

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