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

With no annotations at all, the description carries the burden and does meaningful work: it discloses that the tool is free and requires no payment (explicitly 'no x402 challenge'), and that reports are deterministic/reproducible from the published criteria. It does not discuss rate limits or caching, but for a static zero-argument read that is minor.

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?

Front-loaded with the resource and its contents, followed by the actionable 'read before paying' directive, then the cost note and HTTP equivalent. The content enumeration is dense but each clause adds information; minor redundancy between 'no payment required' and 'no x402 challenge'.

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 zero-parameter, free read with no output schema, the description lists the contents of the returned document, confirms no payment is needed, and gives the HTTP endpoint. There is nothing an agent needs to know to invoke it correctly that is missing.

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 tool takes zero parameters and the schema is empty, so the baseline of 4 applies; there is nothing to document and the description correctly adds no parameter prose.

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 resource and scope: 'The published criteria for the Dialect Check service (payability/v1, family A2)' and enumerates what it contains (modes, six axes, grading rules, cross-leg union semantics, A1 boundary, corpus identity). An agent knows it is a documentation/criteria tool returning the ruleset, not a live check. It does not name dialect_check or dialect_precheck explicitly, so sibling differentiation is only implied by 'Read these before paying'.

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?

Gives a clear directive — 'Read these before paying - every report is reproducible from them' — which effectively says to call this before dialect_check. It does not explicitly name the alternative tools or state when-not-to-use, but the ordering guidance is unambiguous.

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