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

With no annotations, the description carries the full responsibility. It discloses a key behavioral trait: 'Pure URL builder, no server-side state' – essential for an agent to avoid expecting persistence. It also explains the effect on the runner's watch and Strava title. This is valuable beyond a basic action statement, though it could mention more about errors or responses.

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 three concise sentences, each earning its place: purpose, usage timing, and a critical behavioral constraint. It is front-loaded with the primary action and contains no fluff or redundant information.

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 simple 3-parameter tool with no output schema, the description is sufficiently complete. It covers what it does, when to use it, and a key constraint. The return value (a URL) is implied but not explicitly stated, and edge cases are absent, but these are minor for a pure URL builder.

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 adds some semantic context (e.g., the name appears on GPS/Strava), but this is largely redundant with the schema's own parameter descriptions. No additional syntax, formatting, or edge-case behavior is provided, so it stays at the baseline.

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 clearly states the tool's action: 'Compose a builder URL with a dedication pre-filled' – a specific verb+resource. It distinguishes from siblings by focusing on dedications, while siblings like add_cause, export_gpx, find_heart_route_in_city serve different purposes. The added context about the GPS watch and Strava title further clarifies the domain.

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 timing: 'Use after the user picks a route (find/generate) and decides who the heart is for.' This gives a clear workflow context. It doesn't name alternatives or when not to use it, but the 'Pure URL builder, no server-side state' phrase helps distinguish from stateful tools. Lacks explicit exclusions, so not a 5.

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