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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered; the description adds genuine operational behavior — exact totals only when total_relation is 'eq', otherwise a lower bound, and the instruction to narrow rather than page when pagination_limited is true. Some of this overlaps output-schema fields (has_more, next_from), but the guidance on how to act on them is beyond what the schema conveys.

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 first sentence is well front-loaded and information-dense. However, the trailing paragraph 'Complements the main `search` tool: use this to page through a large result set with an explicit offset' restates the opening sentence almost verbatim, adding length without new information.

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?

With annotations covering safety, a full output schema, and 100% parameter documentation, the description only needs to add routing and pagination behavior, which it does. The one residual gap is not distinguishing itself from the other search-flavored siblings, but nothing needed to call it correctly 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?

Schema description coverage is 100% with clear per-parameter docs, including the size/limit alias, from_/next_from continuation, and section enum semantics, so the baseline is 3. The description adds only the general notion of offset paging and section narrowing, not new syntax or format detail beyond the schema.

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 ('Relevance-ranked full-text thread search') plus its distinguishing capability ('explicit offset pagination'), and explicitly positions it against the sibling `search` tool. An agent can tell it apart from `search`, `search_threads`, and `search_posts` without opening a 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?

Gives clear when-to-use: page through a large result set beyond what the main search tool returns, and names that alternative explicitly. It also gives a when-not condition ('if pagination_limited is true, narrow the query or section instead of paging further'). It does not, however, distinguish itself from other search siblings such as search_threads or search_semantic.

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