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). The description adds real value beyond them by disclosing the algorithm (bidirectional BFS) and the deterministic shape of the result (full path plus degrees of separation), which explains why the operation is idempotent. It omits edge-case behavior (e.g., what happens when no path exists).

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?

Three sentences, front-loaded with the purpose, then mechanism/return, then usage triggers. Efficient overall, though 'degrees of separation' appears in both the return statement and the usage triggers, a minor redundancy.

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?

With full schema coverage, complete annotations, and an output schema covering the return shape, the description supplies everything an agent needs: what it computes, how, and when to reach for it. Nothing material is missing.

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%, with both 'from' and 'to' documented as director slugs including examples. The description only says 'any two directors' and adds no format, casing, or validation detail beyond the schema, 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 (find shortest path), a precise resource (two NZX directors connected via shared board seats), and the mechanism (bidirectional BFS over the director/company interlock graph). This clearly separates it from adjacent siblings such as get_director_network or get_company_connections, which cover a single entity's connections rather than a pairwise path.

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 final sentence gives concrete invocation triggers: 'how two directors are connected', 'degrees of separation', and 'the link between two people in the NZX network'. It does not name a specific alternative tool or state when not to use it, so it stops short of the top band.

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