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

Annotations already provide readOnlyHint, idempotentHint, and destructiveHint=false. The description adds value by stating the tool is 'deterministic' and that 'no external action is executed,' reinforcing and elaborating on the annotations. It doesn't contradict annotations, so no annotation_contradiction.

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, front-loaded with the core function, then a usage instruction. Every word earns its place; no redundancy or filler.

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 a rich output schema, complete parameter descriptions, and safety annotations, the description covers purpose, usage, and behavior sufficiently for an agent to select and invoke the tool correctly. It doesn't need to explain return values because the output schema exists.

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 input schema has 100% coverage with each parameter already described. The description adds extra meaning by grouping them into 'request, policy, and optional result evidence,' showing how they relate to the receipt. It doesn't provide syntax details, but the schema already covers that, so this is above baseline.

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 clearly states a specific verb-resource pair: 'Create a deterministic, read-only pre-action receipt' from specified inputs. It distinguishes itself from siblings by emphasizing determinism, read-only nature, and that no external action is executed, making it unique among the listed boundary/checking tools.

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?

Explicitly tells when to use: 'Use before an agent posts, spends, lists, or writes so the decision can be audited.' It also clarifies the critical safety property: 'no external action is executed.' However, it does not explicitly mention alternatives or when not to use, so it stops short of a 5.

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