Exa MCP Server

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

Annotations already indicate this is a safe read-only, idempotent operation. The description adds valuable behavioral context beyond annotations: it specifies the tool provides 'the highest quality and freshest context' and is optimized for 'libraries, SDKs, and APIs.' However, it doesn't mention potential rate limits, authentication requirements, or output format details.

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 with three sentences: purpose statement, quality claim, and usage rule. Each sentence adds distinct value. While concise, the quality claim ('highest quality and freshest context') could be more specific about what constitutes 'quality' in this context.

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 search tool with comprehensive annotations and full schema coverage, the description provides adequate context about purpose, scope, and mandatory usage rules. The main gap is the lack of output schema, but the description compensates somewhat by indicating the type of content returned (programming context). A more complete description would briefly mention the return format.

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?

With 100% schema description coverage, the schema already fully documents both parameters. The description doesn't add any parameter-specific information beyond what's in the schema. The baseline score of 3 is appropriate when the schema carries the full parameter documentation burden.

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 clearly states the tool's purpose: 'Search and get relevant context for any programming task' with specific resources mentioned ('libraries, SDKs, and APIs'). It distinguishes from sibling tools by focusing exclusively on programming-related queries, unlike general web search or company research tools in the sibling list.

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 provides explicit usage rules: 'Use this tool for ANY question or task related to programming' and includes a mandatory directive: 'RULE: when the user's query contains exa-code or anything related to code, you MUST use this tool.' This gives clear when-to-use guidance and distinguishes it from non-programming alternatives.

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