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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds genuinely useful context beyond that: the return shape (contextual snippets with titles and direct links) and the follow-up workflow for full page content. It stops short of mentioning result limits or ranking behavior, so not a 5.

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 with purpose, then usage conditions, then alternatives and return shape. The trailing parenthetical with the `.mdx` example is verbose but directly actionable, so it earns its place; slightly tighter phrasing would reach a 5.

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?

No output schema exists, and the description compensates by describing what search returns and how to get full content afterwards. For a two-parameter read-only search tool with full annotation coverage, nothing an agent needs in order 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 coverage is 100%, so both parameters are already documented, including the language default of 'en'. The description adds no meaning to `query` (no syntax, operators, or phrasing guidance) or to `language` beyond what the schema 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 ("Search across the DarkFunnels knowledge base") and enumerates the content types returned (code examples, API references, guides). It also differentiates itself from the sibling query_docs_filesystem_dark_funnels by scope.

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?

Explicitly says when to use it (answering questions about DarkFunnels, finding documentation, understanding features) and names the alternative for full page content with concrete mechanics (`head`/`cat` on the path with `.mdx` appended, plus a worked example). Nothing is left to inference.

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