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

Annotations already convey that this is a write operation (readOnlyHint=false), but the description adds valuable behavioral details: the receipt is 'tamper-evident,' returns an HMAC-SHA256 signature over canonical JSON, and is 'queryable by session or agent for audit.' This provides context about return format and persistence beyond the annotations.

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 three sentences, front-loaded with the main purpose, then usage timing, then return value and auditability. Every sentence carries necessary information with zero waste. The structure is ideal for quick agent parsing.

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?

For a tool with 15 params and no output schema, the description covers key contextual needs: when to call it, what it returns (receipt ID + HMAC), and why it matters (proof of integrity, auditability). It does not detail error cases or prerequisites, but the schema and annotations cover parameter requirements. This is reasonably complete for an agent to invoke it correctly.

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 the schema already fully documents all 15 parameters. The description does not add meaning to individual parameters; it only references 'canonical receipt JSON' globally. Per the baseline rule, a score of 3 is appropriate since no additional param-level insight is provided.

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 the tool's function with a specific verb and resource: 'Record a tamper-evident signed receipt for an agent financial action.' It further distinguishes itself from sibling settlement tools by instructing to call it 'immediately after every successful settlement,' framing it as the post-settlement audit step.

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?

Explicit usage context is provided: 'Call immediately after every successful settlement.' This tells the agent when to use the tool, though it does not explicitly mention when not to use it or name alternative tools. The auditability note implies suitability for record-keeping but lacks direct exclusions, so a slight deduction applies.

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