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

The description substantially exceeds what annotations declare. Beyond the read-only/destructive hints, it discloses async behavior (paging/csv return operation IDs requiring checkOperationStatus polling), caching side effects (creates cached table on first paging call), query transformations (field operators stripped, forward slashes treated as spaces), and the requirement that aggregate fields be explicitly requested. The final line 'This is a safe, read-only tool' is consistent with readOnlyHint=true and destructiveHint=false. No contradiction; it adds rich behavioral context beyond structured data.

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 well-organized with labeled sections (USE CASE, RESPONSE MODES, PAGING MODE DETAILS, QUERY SYNTAX, FILTERS, AGGREGATE FIELDS) and is front-loaded with the core purpose. There is some redundancy with the schema — the query syntax is explained both in the description and in the query parameter's schema text — and the 'IMPORTANT!!!!!' year warning is noisy. Given 16 params and 3 response modes, the density is largely justified; it earns most of its sentences.

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 16-parameter tool with no output schema, the description is remarkably complete. It covers all three response modes and their return behavior (up to 300 results, operation IDs for paging, S3 link for CSV), the full paging lifecycle, query syntax with boolean operators and @handles, all filter semantics including the date behavior and year-verification caveat, and aggregate field requirements. The only minor gap is no explicit pagination default behavior statement, but this is covered. Nothing an agent needs to invoke it correctly across modes 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?

With 81% schema coverage, the baseline is 3, and the schema already documents query, fields, limit, responseType, and paging params thoroughly. The description adds genuine value beyond the schema by explaining the paging workflow (omit pageNumber/tableName on first call, use returned tableName for subsequent pages, pageNumberEnd for bulk fetch) and clarifying aggregate fields (aggRelevance, relevantPostsCount) that must be explicitly requested. It does not repeat param names but explains their interaction, which is the useful complement.

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 states a specific verb+resource: 'Search for USERS who authored Reddit posts matching keywords.' It clearly differentiates from siblings like getRedditPostsByKeywords and getRedditCommentsByKeywords by emphasizing 'USERS who authored' and 'Returns unique, deduplicated user profiles.' The use case is stated explicitly and the scope (users, not posts/comments/subreddits) is unambiguous.

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 provides a clear USE CASE ('Find users who have posted content about specific topics') and detailed operational guidance on response modes, filters, and paging. However, it never explicitly routes the agent away from alternatives like getRedditPostsByKeywords or searchRedditUsers, so exclusions are left to the agent to infer. It has clear context but no explicit when-not-to-use guidance, matching the 'clear context, no exclusions' level.

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