search-spans

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

Annotations already declare readOnlyHint and openWorldHint, so the agent knows it's a safe, read-only operation. The description adds no additional behavioral traits (e.g., rate limits, authentication needs, or result structure). The description repeats filter capabilities that are already in the schema, adding minimal value beyond annotations.

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 a single, concise sentence that conveys the purpose and key filtering capabilities without redundancy. It is front-loaded with the main action and domain, making it efficient for agent scanning.

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 good parameter documentation, the description covers the essential purpose and filter dimensions. However, it lacks information about return values, pagination (limit parameter exists but no explanation of result format), or any behavioral details like sorting default. With no output schema, more context on result structure would improve completeness.

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 baseline is 3. The description adds value by listing example filter fields (service, resource, status, duration) that likely correspond to the query syntax, providing practical guidance beyond the schema. This helps agents construct effective queries.

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 searches APM spans/traces for performance analysis, specifying the domain (APM) and the action (search). It differentiates from sibling search tools like search-logs or search-ci-pipelines by focusing on spans/traces. However, it could be more explicit about the resource type (spans/traces) to avoid ambiguity.

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 implies usage for APM performance analysis and filtering by common fields, but it does not explicitly state when to use this tool versus alternatives (e.g., search-logs for logs, list-services for services). No guidance on when not to use it is provided, but the domain specificity gives some context.

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