Read Email

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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds genuinely non-obvious behavior beyond that: single-page returns with has_more/next_offet continuation ('Only has_more: false means you have seen everything') and windowed bodies via body_truncated/body_next_offet. No contradiction with 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?

Four short sentences with zero filler. The purpose is front-loaded in sentence one, and each of the two protocol traps (page continuation, body windowing) gets one dense sentence that earns its place. Nothing is redundant with the schema.

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 30-parameter, 7-action tool with no output schema, the description captures the trickiest protocol contract — pagination and body windowing — that an agent would most likely get wrong. Operational details like per-action semantics, the 10 MB attachment budget, inbox disambiguation, and provider quirks are carried by the thoroughly described schema, so the division of labour is reasonable. Return shapes aren't covered, but the absent output schema makes that a minor gap.

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%, and the parameter docs already explain the continuation semantics (offset: 'Pass the previous response's next_offset exactly'; body_offset: 'Pass back body_next_offset to continue a truncated body'). The description reinforces this at the protocol level but adds little the schema didn't already say, so the baseline 3 applies.

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 states a specific scope: 'Read, list and search email in one inbox.' The verbs (read, list, search) name the concrete operations and the resource is unambiguous. It doesn't explicitly differentiate from siblings like inbox_list or email_organize, but the operation set is precise enough that an agent can tell what this tool does at a glance.

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?

The description gives no explicit when-to-use-vs-alternatives guidance for sibling tools. It does teach the pagination loop within the tool, and the schema's `action` parameter description routes the agent to the right action (list/read/read_batch/search/attachment/extract/original) with per-action semantics. This is implied rather than explicit guidance, so a 3 fits.

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