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

Annotations already declare readOnlyHint=true, so safety is covered, but the description adds genuinely useful behavioral context: the response is metadata-only and deliberately excludes card numbers/PII. That is exactly the kind of trait annotations can't express and it also names the backing endpoint. It stops short of describing pagination mechanics or result limits.

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?

Two sentences, tightly front-loaded with the action and return shape, followed by the key limitation and the API mapping. Every clause carries information; nothing is redundant.

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 usefully enumerates returned fields and explicitly states what is omitted, which is the critical fact for an agent handling token data. The only remaining gap is any note on pagination beyond the cursor parameter already documented in the schema.

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%, with each of the five parameters (size, type, start, container, fingerprint) documented including cursor semantics and the duplicate-detection use of fingerprint. The description adds no parameter-specific meaning beyond that, so the baseline 3 applies.

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 verb and resource ('List vault tokens') and enumerates the returned fields (id, type, container, fingerprint, metadata, timestamps), which goes beyond the name. It clearly distinguishes itself from single-entity read siblings like get_token, though it doesn't name search_tokens as the alternative for richer filtering.

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 'Does not return the underlying card number or PII' clause implicitly tells the agent this is a safe metadata-listing operation as opposed to a value-revealing one, which is useful routing context. However, there is no explicit statement of when to prefer this over search_tokens, nor any prerequisite/exclusion guidance.

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