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

Annotations already declare readOnlyHint=true, and the description adds meaningful behavioral context beyond that: it mentions conditional execution ('when approved geometry exists'), the nature of results (temporal validity, N-way successor context, topology, etc.), and 'No payment required' as an operational note. It does not contradict annotations and provides useful transparency about output semantics.

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 five sentences, each earning its place: purpose, return content, usage context, caveat, alternative, and payment status. It is front-loaded with the primary purpose and uses clear, direct language without 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?

Given the tool's complexity (9 params, anyOf input patterns, no output schema), the description adequately summarizes the return categories and usage nuances. It does not describe batch behavior via 'items', but the schema covers that. Slight room remains to mention asynchronous or batch limitations, but overall it is complete enough for selection and invocation.

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?

The input schema has 100% parameter description coverage, so the schema already documents all parameters. The tool description itself does not detail individual parameters but instead gives high-level context about the tool's purpose. This meets the baseline for a schema-heavy tool, though it adds no extra parameter-level meaning.

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 opens with 'Detailed relationship tool for two geographic identities' which clearly states the verb (compare/relate) and resource (two geographic identities). It further distinguishes from siblings by explicitly positioning it 'after a compact point lookup when the caller asks whether two tiers/releases really contain or overlap one another' and directs users to resolve_reference for name resolution.

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 description provides explicit when-to-use guidance ('Use this after a compact point lookup...'), an alternative ('Use resolve_reference first for names or outside identifiers'), and a key caveat ('A point-chain seam is not proof of strict parentage'). This fully covers usage context and distinguishes when to select this tool over siblings.

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