discover

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

The description declares 'Read-only: performs no writes,' which aligns with the readOnlyHint annotation, and adds valuable behavioral context: 'Requires authentication (app password)' and 'Subject to per-tool rate limiting.' This goes beyond the annotations to inform the agent of key operational constraints.

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 extremely concise, containing only three sentences that cover purpose, authentication, read-only nature, modes, sibling differentiation, and rate limiting. Every sentence adds value with no redundancy or filler. The most critical information is front-loaded.

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?

Given the tool's complexity (11 parameters, two modes) and the presence of an output schema, the description is nearly complete. It covers purpose, authentication, read-only behavior, mode overview, sibling tools, and rate limiting. The only minor gap is not explicitly stating that results vary by mode, but this is inferred from the schema. The output schema handles return values, so no additional description is needed there.

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 the input schema already provides detailed parameter descriptions. The tool description adds no new parameter-level information beyond the schema, resulting in a baseline score of 3. Nothing in the description enhances the semantic understanding of parameters beyond what the schema offers.

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: 'Surface content from your own home timeline.' It specifies two modes and distinguishes from sibling tools by naming alternatives (find_similar_users, discover_communities). The verb 'surface' combined with the resource 'home timeline' makes the purpose specific and unambiguous.

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?

Explicit guidance on when to use this tool versus alternatives is provided: 'For finding accounts similar to a given user use find_similar_users; for topic-based communities use discover_communities.' Additionally, it notes authentication requirements and rate limiting, giving clear context for proper usage.

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