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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds meaningful context: search results include 'contextual content with titles and direct links,' and it explains the .mdx path convention for following up with the filesystem tool. This goes beyond the annotations and helps the agent predict behavior.

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 four sentences, each earning its place: purpose, when-to-use, return format, and cross-tool follow-up with a concrete example. It is front-loaded with the core purpose and contains no redundant or filler text.

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 one-parameter, read-only search tool, the description covers all needed context: what it searches, when to use it, what the response looks like, and how to retrieve full page content via a sibling tool. Nothing required for a correct invocation 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?

The input schema fully documents the single `query` parameter with 'Search query' at 100% coverage, so the description does not need to add parameter explanations. The description does not introduce query syntax or formatting details, so it stays at the baseline for fully documented schemas.

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 states a specific verb and resource: 'Search across the TheRundown API knowledge base to find relevant information, code examples, API references, and guides.' It also explicitly contrasts with the sibling query_docs_filesystem by directing users there for full page content, making the tool's role unmistakable.

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 provides explicit scenarios: 'Use this tool when you need to answer questions about TheRundown API, find specific documentation, understand how features work, or locate implementation details.' It also names the alternative and the condition for using it ('If you need the full content of a specific page, use the query_docs_filesystem tool'), so there is no ambiguity about when to choose this tool.

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