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

Annotations already cover safety (readOnly, idempotent, not open-world), and the description adds material beyond them: a per-call price of $0.05 settled over x402 (USDC on Base), plus the shape of the result ('code length, precision in metres and validity'). It does not address failure modes or invalid-input behavior, so it stops short of a 5.

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 dense sentences, front-loaded with the core encode/decode purpose before the less obvious shorten/recover modes and the pricing tail. Every sentence carries distinct information; nothing is redundant with the schema.

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 no output schema, the description compensates by naming the returned fields (code length, precision in metres, validity), and it discloses the payment model. It leaves some ambiguity about which ops return which fields and about invalid-code handling, so it is strong but not fully complete.

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, but the description adds real meaning: it ties length to a 'chosen' precision, and explains that ref_lat/ref_lon act as the reference coordinate for shorten/recover, clarifying the relationship between the coordinate and code params across ops.

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+resource set: encode coordinates to an Open Location Code, decode a code to bounding box and centre, shorten against a reference, and recover a shortened code. This clearly separates it from siblings like geo_geohash and geo_distance without needing their schemas.

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 explains what each op does and notes shorten/recover reflect 'how plus codes are normally exchanged in text', which implies usage, but it never states when to pick this tool over a sibling (e.g., geohash) or when each op is inappropriate. Usage is implied rather than prescribed.

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