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

Annotations already establish that this is read-only, idempotent, and non-destructive. The description adds useful behavioral context: the search returns 'contextual content with titles and direct links' and implies it does not return full page bodies, which is an important caveat. It also gives an explicit path to obtain full content via the filesystem tool.

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 efficiently structured: the first sentence defines the tool, the second gives usage criteria, the third describes the return format, and the fourth explains the alternative for full content. Every sentence earns its place with no filler or redundancy.

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 low-complexity search tool with read-only annotations, this description is complete. It covers what the tool does, when to use it, what it returns, and how to retrieve full page content when needed. The absence of an output schema is not a gap because the description explicitly states the return shape.

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 both the 'query' and 'language' parameters are already documented in the schema. The description adds no parameter-specific meaning beyond the general search behavior, which matches the baseline of 3 for high schema coverage.

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 opens with a specific verb and resource: 'Search across the DarkFunnels knowledge base to find relevant information, code examples, API references, and guides.' It also states the scope of what search covers and differentiates itself from the query_docs_filesystem sibling by clarifying that search returns titles and links rather than page content.

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 explicitly says 'Use this tool when you need to answer questions about DarkFunnels, find specific documentation, understand how features work, or locate implementation details.' It also provides a clear alternative: 'If you need the full content of a specific page, use the query_docs_filesystem tool.' This gives the agent both the when-to-use and the when-not-to-use conditions.

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