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

Annotations already establish readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds real value beyond them: results are capped and de-duplicated by name, and the agent is told to narrow the query or try list-account-parties if nothing is found. It does not discuss failure/empty-result semantics beyond that fallback, keeping it out of the top band.

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?

Front-loaded with the core action, then disambiguation, then usage bullets, then a fallback note — a logical ordering with no wasted framing. It runs somewhat long and restates the account-party contrast twice, which keeps it from a 5.

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 two-parameter read-only lookup with an output schema and full annotation coverage, the description supplies everything an agent needs: what it searches, what it excludes, the cap on results, and which sibling to try next. No behavioral or routing question is left open.

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% for both parameters (query and limit, including min/max lengths), so the schema already carries the detail. The description only adds that matching is against the underlying entity_name field, which is marginally useful but largely duplicative. Baseline 3 is appropriate.

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 and resource ('Search the account's external parties ... by name') and immediately contrasts it with the sibling list-account-parties. An agent can tell exactly what this returns and how it differs from the nearest alternative without opening any schema.

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?

Provides an explicit 'Use this tool when' list (need a party name to filter list-documents; want to find matching parties) plus a when-not rule with a named alternative (phrasing like 'our'/'we' means an account party, use list-account-parties). It even prescribes a fallback order before concluding a party does not exist.

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