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

Annotations already declare readOnlyHint=true, so safety is covered; the description adds genuinely new behavior: newest-first ordering, cursor-style paging via 'before', the per-message event timeline, and the delivered-vs-not semantics of outcomes. Return shape is sketched (id, sender, recipients, subject, outcome) despite no output schema.

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-loads the resource scope, then splits cleanly into 'action list:' and 'action get:' segments. Dense but every clause carries information; the em-dash-heavy style is slightly harder to parse than plain sentences.

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 7 params, no output schema and read-only annotations, the description still gives an agent everything needed: what each mode returns, ordering, paging, and how outcomes map to delivery state. Nothing essential for correct invocation 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%, so parameters are already documented in the schema, making 3 the baseline. The description reinforces the outcome filter and id usage but adds little beyond what the schema's own descriptions state, and it doesn't mention person/project scoping at all.

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 resource and scope: 'the emails this workspace sent and what happened to each', with the two actions (list/get) distinguished. An agent can tell this apart from email_send or email_drafts by the 'sent' framing, though no sibling is named explicitly.

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?

Clearly delineates the two modes: 'action list' returns a newest-first roster, 'action get' returns one message with its event timeline. The outcome filter is explained as separating delivered from not-sent/scheduled mail. No explicit when-not or routing to email_send/email_drafts, so short of 5.

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