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

No annotations are provided, so the description carries the full burden, and it discloses nothing about side effects, auth requirements, scope of 'own', or whether it is a read or a state change. The word 'validity' hints at a check but never states what is validated or against what.

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?

At five words it is short, but this is under-specification rather than conciseness: the fragment lacks a verb and gives the agent nothing front-loaded to act on. Every word is technically wasted because none resolve what the tool actually does.

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 annotations, no output schema, and a fragmentary description, an agent cannot determine what this tool returns or when it applies. For a zero-parameter tool in a six-tool family, the definition is far too thin to support correct selection or invocation.

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, so per the rubric this is a baseline 4. The description does not need to compensate for any parameter documentation gap.

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 phrase 'Own receipt chain + validity' names a resource (receipt chain) and an attribute (validity) but supplies no verb, so it is unclear whether the tool fetches, lists, verifies, or mutates receipts. It also fails to distinguish itself from nearby siblings like attestation_check and verdict_lookup, which plausibly cover overlapping validity-checking territory.

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 indication of when to call this tool, what precondition triggers it, or how it differs from attestation_check, verdict_lookup, or probe. An agent has no basis for choosing between these five siblings.

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