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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower, and the description still adds real operational context: a hard cap of 10 results, the opaque-id contract, and the empty-result condition when the index is empty or nothing matches.

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?

Four dense sentences with the purpose front-loaded and no filler; the constraint on result count and the fetch handoff each earn their place. It is slightly longer than strictly necessary but well structured and skimmable.

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?

No output schema exists, and the description compensates by describing the return shape: up to 10 candidate matches across named entity types, each with an opaque id for follow-up retrieval, plus the empty-result case. The main omission is result ranking/score semantics, but an agent has enough to call and consume this tool correctly.

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 coverage is 100% and the single 'query' parameter is fully documented in the schema (natural-language, 1-500 chars). The mention of a 'hybrid BM25 + vector index' implies natural-language phrasing is what the index expects, but it adds little about how to shape the query beyond what the schema already says, so the baseline 3 applies.

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?

States a specific verb+resource ('Discovery tool for the Onplana org') and enumerates the entity types it searches (projects, tasks, risks, comments, wiki pages) plus the result cap of 10. It does not differentiate itself from the sibling search tools (search_docs, search_org_knowledge), leaving ambiguity about which discovery entry point to pick.

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?

Gives explicit when-to-use guidance ('Use this BEFORE attempting any list scan') and names the downstream sibling ('id can be passed to the fetch tool'), which is genuinely actionable routing. It omits when to prefer search_docs or search_org_knowledge over this tool, so the guidance is clear context without full alternative coverage.

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