Plan Fiber Leadin

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context by warning that results are 'INDICATIVE auto-routed road corridors — NOT engineered alignments; subject to survey, DBYD and carrier confirmation'. This discloses uncertainty and limitations beyond what annotations provide.

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 front-loaded with the core purpose, followed by the question it answers, an example, parameter summary, return summary, caveats, and exclusions. It is longer than necessary partly because the parameter recap overlaps with the schema, but every section adds either clarity, usage routing, or caveats, so the length is largely justified.

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 has an output schema and safety-relevant annotations, the description is complete: it provides an example, explains the core outputs, discloses the indicative nature of the results, and names the sibling alternatives to avoid. Nothing needed to invoke the tool correctly is missing, and the caveat about survey/DBYD/carrier confirmation adds important real-world context.

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% and the schema already documents all five parameters clearly, including formats, defaults, and ranges. The description's param recap largely duplicates the schema, though it adds the concrete from/to example and clarifies the relationship between fibre count and cost estimation. This meets the baseline for high schema coverage but does not substantially extend it.

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 names a specific verb and resource: 'Plan N diverse, road-following fibre lead-in routes' from a candidate site to a carrier hotel/POP. It states the exact question it answers and explicitly distinguishes itself from nearby siblings by saying to use analyze_site and get_fiber_intel for other use cases. The example with concrete addresses further anchors the purpose.

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 gives clear when-to-use context: answering 'can I get N diverse fibre routes into this site, how far, how much, and where do they share a corridor?'. It also names exclusions and alternatives explicitly: 'Do NOT use for a single site-suitability score (use analyze_site) or fibre-provider footprints (use get_fiber_intel)'. This routes an agent to the correct tool without ambiguity.

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