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

Goes well beyond the readOnlyHint annotation: it discloses the HMAC-SHA256 signature over canonical JSON, the exact contents of the payload (event trail plus totals), the owner-scoping authorization constraint, and candidly bounds what the proof means (observed vs. a qualified ERDS receipt). That is exactly the kind of trust-relevant context an agent cannot infer from schema or 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?

Front-loaded with the action and artifact, then the mechanism, then the caveat — a sensible order. Slightly dense with jargon ("RMail-style", "mosadd") that costs a little readability, but no sentence is 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?

There is no output schema, and the description compensates by describing what the report contains (event trail, print/copy/forward signals, totals, signature). Scope, authorization and limitations are all covered, so an agent has everything needed to call it and interpret the result.

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 single message_id parameter is fully documented in the schema (100% coverage), including that it comes from mAYL_send or inbox. The description adds only the implicit constraint that the message must be a sent email; with one well-documented param, baseline 3 is appropriate.

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 (Export) and a precisely scoped resource (a tamper-evident engagement audit report for one sent email), plus the contents of that report. It is clearly distinguishable from siblings like mAYL_events, mAYL_metrics and mAYL_stats which read raw engagement data rather than a signed export.

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?

"For legal/compliance use" plus the HONEST LIMIT note gives clear conditions for reaching for this tool rather than raw event/stats endpoints. It stops short of naming an explicit alternative or stating when-not to use it (e.g. for bulk export or non-compliance inspection).

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