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

Although annotations already declare readOnly, idempotent, non-destructive and closed-world, the description adds substantial behavior the annotations cannot convey: only the `received` status is exposed, triage states are deliberately hidden, title and body are never returned, and the count of messages you have sent is included. It also discloses the security posture that wrong, malformed, missing and foreign receipts are intentionally indistinguishable as `not found`, which prevents an agent from misreading an error as a bug.

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?

It is front-loaded with the purpose, then receipt, then return values, then privacy, then alternatives — a sensible order with no filler sentences. It loses a point for redundancy: the indistinguishability of wrong/malformed/foreign receipts is stated twice, once in prose and again as 'A missing receipt, a malformed one and another user's receipt cannot be told apart on purpose.'

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?

There is no output schema, so the description must define the return payload, and it does: status, operator messages, and sent-message count, plus what is deliberately withheld. For a single-parameter read tool with full annotation coverage, nothing an agent needs to call it and interpret the result is missing.

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% and the single `receipt` parameter is already documented as the `ps_…` string from report_security, so the baseline is a 3. The description earns an extra point by giving the parameter's failure semantics: a wrong or foreign receipt produces the same `not found`, so the agent should not retry or reinterpret that result.

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 opening line states a concrete verb and resource ('WHERE YOUR PRIVATE SECURITY REPORT GOT TO') and immediately constrains the scope to a receipt-scoped lookup of report status rather than the report content itself. It also implicitly separates this from report_security (which files the report) and security_reply (which continues the thread), so an agent can choose without opening a schema.

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 the agent when to call it ('Call it with the `ps_…` receipt report_security handed you') and names the alternative for a different need ('Use security_reply to add follow-up detail'). It even covers an edge case with a routing instruction: if the account email cannot receive mail, say so in the operators' thread rather than opening a second report.

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