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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only states 'No identifiers are retained,' which is a privacy/retention note but says nothing about the actual operation: does it make network calls, access the filesystem, mutate state, or return a classification? It does not describe any side effects or safety implications. The description is nearly silent on behavior beyond the vague 'classify' and the privacy note.

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 only two short sentences, which is efficient in word count but severely under-specified. It is front-loaded with 'Show how this request is classified,' but that statement is so vague it offers no value. The second sentence about identifiers is a minor privacy note. Conciseness should be balanced with completeness; here the brevity is a defect, not a virtue.

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?

Given 9 optional parameters, no annotations, no output schema, and a tool name that suggests a cross-domain classification, the description is grossly incomplete. An agent has no idea what inputs are expected, how they are combined, what the classification result looks like, or how to interpret the output. The description does not enable correct invocation at all.

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 100%, so each parameter already has an individual description (e.g., 'Git ref name; discarded after the shape check'). The tool description itself adds no additional meaning about how parameters relate to the classification or what constitutes a 'compatibility' check. Since the schema already covers parameter semantics, the baseline of 3 applies, but the description contributes zero extra insight.

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 'Show how this request is classified' is extremely vague. It does not specify a clear verb+resource (e.g., 'classify a URL' or 'determine compatibility of a GitHub repo') and provides no differentiation from the many sibling tools like normalize-url, validate-json, or domain-shape. The purpose is essentially unstated—'classified' could mean anything, and the tool name 'compatibility' offers only a hint. This fails to tell an agent what the tool actually does.

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 versus alternatives. No mention of scenarios, prerequisites, or exclusions. The sibling tools cover specific domains (URL checks, JSON validation, timezone lookups, etc.), but this description does not say whether 'compatibility' is a general fallback or a specific check. An agent cannot decide between this and a sibling based on the description.

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