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

Annotations already declare readOnly, idempotent, non-destructive, so the safety profile is covered. The description adds genuine behavioral context beyond that: the tool operates in three distinct modes with materially different outputs (company board vs. a person's full network vs. a whole-market map), which is information annotations cannot convey.

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 verb and resource, then modes, then trigger keywords; each block earns its place. The keyword list is long, but it is routing value rather than filler, and the whole thing fits in two sentences.

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 an output schema present, the description needn't document return values, and it nonetheless sketches what each mode surfaces. Mode routing, parameter roles, and trigger vocabulary are all present, so an agent has everything needed to call it 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%, so the baseline is 3. The description earns above baseline by clarifying the mutual exclusivity of ticker/director and what happens when neither is supplied (network mode), resolving an ambiguity the schema only hints at with "Omit for director or network mode."

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 ("Analyze director network patterns") and immediately enumerates the scope: cross-directorships, board interlocks, shared entities. The three-mode breakdown makes it clearly distinguishable from narrower siblings like get_chair_network or get_company_connections, which cover only one slice of the same graph.

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 explicit routing: which parameter selects which mode (ticker for company, director for person, neither for NZX-wide), plus a rich list of trigger phrases ("board interlocks", "overlapping boards", "who sits on multiple boards"). It does not name an alternative tool or state when NOT to use it, so it stops short of a 5.

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