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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds genuinely useful context beyond that: the required gmail.compose scope and the reconnect hint for accounts connected before the feature existed, which an agent could surface to the user.

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?

A single front-loaded sentence that packs purpose, returned fields, the id source, and the auth requirement without waste. Slightly dense with em-dashes, but every clause earns its place.

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 read-only fetch with no output schema, the description helpfully enumerates the returned content fields and names the auth scope. With annotations and a fully described schema in place, nothing essential 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 both parameters (account, draft_id) are already documented in the schema. The description only restates that draft_id comes from list_drafts and lists the fields returned; it adds no syntax or format detail beyond structured data, 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?

States a specific verb+resource+scope: 'Fetch one Gmail draft's full editable content' and even enumerates the returned fields. An agent can distinguish it from list_drafts, get_thread, and update_draft 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?

It tells the agent where draft_id comes from (list_drafts), which implies the fetch-after-list workflow, but gives no explicit when-to-use vs when-not guidance or differentiation from siblings like get_thread or update_draft. Usage is inferred rather than stated.

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