Docs Index

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered structurally. The description adds the llms.txt format detail and the optional filtering behavior, which is helpful context. It does not disclose return format or pagination, but for a simple read-only fetch the annotations carry most of the burden.

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 13-word sentence that front-loads the core action and then states the optional modifier. Zero filler, every word 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?

For a simple one-parameter fetch tool with a strong annotation safety profile, the description is mostly adequate. The gap is that it does not clarify the relationship with siblings (docs_search, docs_list_sections), and with no output schema the agent only learns the response is an 'index' or llms.txt text rather than its structure. Routing guidance would complete it.

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% and the single 'section' parameter is already documented with an example ('SERP API'). The description's mention of 'optionally filtered by section' reinforces the parameter's purpose but adds no syntax or format details beyond what the schema provides, so the baseline of 3 is appropriate.

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 uses a specific verb ('Fetch') and a precise resource ('DataForSEO API documentation index (llms.txt)'), and notes the optional section filter. It is clear what the tool does, though it does not explicitly contrast itself with siblings like docs_search or docs_list_sections, leaving some differentiation to inference.

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?

There is no guidance on when to use this tool versus the sibling tools. The description mentions optional section filtering but never routes the agent to docs_search for queries or docs_list_sections for browsing sections. A clear when-to-use/when-not-to-use statement is absent.

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