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

No annotations are provided, so the description carries the full burden. It does add genuine behavioral context by disclosing the auth mode ('paid') and price ($0.005 per call via x402/MPP), which the agent cannot get from structured fields. It omits, however, what the tool returns (e.g. a format label vs. a structured object), how ambiguous or unrecognized strings are handled, and whether detection is locale/length constrained.

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 payload is dominated by machine-generated keyword spam ('Keyword: uuid', 'Keyword: email validation', etc.), origin URL/hostname/brand metadata, and a duplicated summary ('Summary' and 'Source description' are identical strings). The actual purpose is buried after the origin boilerplate rather than front-loaded, so structure works against fast scanning.

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 one-parameter, no-output-schema utility, the description supplies enough to attempt a correct call: it names the input as a string, lists supported formats, and gives use cases. It is incomplete in that nothing describes the return value (format name, confidence, or 'unknown' handling) and the parameter itself is undocumented in both schema and description.

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 0% and the single 'value' parameter has no description in the schema. The description partially compensates by framing the input as a string whose format is being detected, but it never names the parameter or clarifies expected input shape (encoding, length limits, single vs. multiple values). Baseline-adequate but not additive.

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 summary line states a specific verb and resource ('Detect the format of a string') and enumerates the detectable formats (uuid, email, url, ipv4, ipv6, jwt, iban, mac, semver), which lets an agent distinguish it from adjacent siblings like detect_encoding (charset) and script_detect (writing system). It stops short of explicitly naming those siblings, so the differentiation is implied rather than stated.

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 three 'Use case' lines give concrete scenarios ('tell me whether this string is a UUID, an email or a JWT', 'detect the format of a token before parsing it'), which conveys when the tool applies. However, there is no guidance on when NOT to use it or how it differs from script_detect/detect_encoding for overlapping inputs, so the routing guidance is only implicit.

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