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

Beyond the annotations it discloses real behavioral traits: results are bounded and page-cited, sequential reads are resumable via next_cursor, and unmatched material is never surfaced as verified evidence — a meaningful quality guardrail. Note the annotations declare readOnlyHint=false for what the description frames as a pure retrieval operation; this is an inconsistency worth confirming, though it may reflect server-side cursor state rather than a write.

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?

Front-loaded and free of filler, with the two modes stated up front. However, the Chinese sentence is a full duplicate of the English one, roughly doubling the description's length without adding information, so not every sentence earns its place.

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 an output schema present, return-shape explanation is not required, and the description covers both modes plus the no-false-evidence guardrail for a 7-parameter tool. The remaining gap is the absence of any relationship to the search_* siblings that supply source_type and source_id.

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%, so every parameter (query, cursor, start_page, max_passages, reading_mode, source_id, source_type) is already documented in the schema. The description adds only the tool-level link between sequential mode and next_cursor, which the schema already states, so the baseline 3 applies.

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: 'Return bounded, page-cited source excerpts, or a sequential reading window... for whole documents', and names the two operating modes. It never mentions the sibling search tools, so an agent relies on the schema line 'Source identifier returned by a search tool' to infer the retrieve-after-search pairing.

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?

It implicitly distinguishes the two modes ('reading_mode="sequential" with next_cursor' for whole documents vs. excerpts for a claim), which is useful mode-selection guidance. It gives no explicit rule for when to call this instead of search_filings/search_meetings/search_research, and no guidance on behavior when the query yields no match beyond the guardrail sentence.

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