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

Annotations already cover read-only/idempotent/non-destructive, and the description adds substantial context beyond them: it discloses the exact fetch targets, that it mirrors what a checkout agent sees, that results are validated against published JSON Schemas and the vocabulary, and that 'nothing is stored'. It also describes the return shape (verdict ready|partial|none, one line per step, errors/warnings, missing items with fix locations).

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 verification question is front-loaded and every clause is informative, but the core content is a single long run-on sentence that could be split for scanability. Nothing is redundant, though.

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 carries the return contract itself and does so thoroughly: verdict values, per-step lines, what the agent sees, and what is missing plus where to fix it. For a two-parameter read-only probe this is 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 both parameters are already documented, and the baseline applies. The description explains the fetch paths and the register-driven flow but does not clarify the optional `document` override beyond naming a vendor declaration path, leaving its precedence over the default path implicit.

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 opens with a concrete question ('Does an agent find PTPGE on this domain?') and enumerates exactly what is fetched (.well-known/ucp manifest, ptpge block, declaration.json, vendors register, supplier catalogue). This is clearly distinct from siblings like ptpge_validate_document, which validate a single supplied document rather than probing a live domain.

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?

It gives explicit usage contexts: 'is <printer> agent-ready?' and 'why does my declaration not validate?'. It does not explicitly contrast with ptpge_validate_document or ptpge_fingerprint, so the agent must infer which to pick when it already has a document in hand.

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