List Email Tests

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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint=false), yet the description still adds non-structured behavior: the required monitoring:read token scope, the newest-first ordering guarantee, and the instruction to render report_url as a clickable link. The auth requirement in particular is behavioral context annotations cannot express.

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 usage trigger and the auth prerequisite, then the return shape, so the most decision-relevant content comes first. The mid-sentence enumeration of eight return fields makes it dense, but with no output schema that detail is load-bearing rather than 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, so the description carries the return-value burden itself and does so by naming each field (test_id, status, created_at, received_at, from_domain, score/out_of, dmarc_result, report_url). Together with the trigger condition, auth scope, ordering, and follow-up routing, an agent has everything needed to call and use this tool.

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 description coverage is 100%, so both parameters (limit, domain) are already documented including the default and the 1..50 bound. The description's "optionally only those whose From names one organization" restates the domain filter without adding format or edge-case detail beyond the schema's own example.com note.

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+resource (list email tests) and scopes it to the account's own past tests, newest first. It explicitly distinguishes itself from the sibling get_email_test, which it directs the agent to for a single test's full result.

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?

"Use this when a signed-in user asks about email tests they ran before, or how a sender's earlier tests scored" gives a concrete trigger, and "call get_email_test with a test_id for the full result" names the alternative and the condition that selects it.

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