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

With no annotations, the description must carry the full transparency burden. 'Value discarded' hints that the tool is stateless, but it does not disclose whether the call is read-only, whether any external access occurs, what it returns, or how errors are surfaced.

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 short, but this is under-specification rather than effective conciseness. It is a fragment with no front-loaded action and omits essential invocation detail.

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 tool with 10 optional parameters, no annotations, no output schema, and a confusing schema alignment, the one-line description is almost completely inadequate. It never explains the return value, which parameter to populate, or how the shape check behaves.

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?

Although the schema covers all 10 parameters, the description adds no parameter mapping and creates a mismatch: it talks about a bigint shape while every parameter is a string for refs, URLs, cities, JSON, and similar values. An agent cannot tell which field, if any, should hold the unsigned 64-bit decimal value.

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 identifies the domain — unsigned 64-bit decimal shape — and 'shape' implies a validation check, so it is not a pure tautology. However, it is a noun fragment with no explicit verb such as 'checks' or 'validates', and the 10 unrelated schema parameters make the exact purpose harder to pin down.

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?

There is no guidance on when to use this tool instead of a sibling such as validate-json, domain-shape, or file-path-ok. No alternatives, prerequisites, or exclusions are mentioned, so an agent gets no help with selection.

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