gmail_get_thread

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

Adds substantial behavior beyond the readOnlyHint/openWorldHint annotations: ADC credential use, the mandatory quota-project header, the 100,000-character body budget shared newest-first, header-only retention with body:null past the budget, the omittedBodies escape hatch, and a 1 MB cap for raw formats.

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 core purpose, then organized into Args/Returns sections. Most detail earns its place, though the credential/header note is slightly incidental to selection and the format explanation is dense.

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 two-parameter read tool this covers everything an agent needs: credential requirements, format semantics, truncation behavior and recovery path, plus the return shape (also backed by an output schema). Nothing material 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 description coverage is 0%, so the description carries the full burden and does: thread_id is defined as the threadId of any member message, and every format value ('text' default, 'metadata', 'minimal', 'full') is explained with its decoding and size behavior.

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 and resource ('Fetch a whole Gmail thread') plus a scoping detail (oldest message first) that immediately distinguishes it from gmail_get_message, which the description names as the follow-up tool for omitted bodies.

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?

Usage is implied rather than stated: fetching a whole thread versus a single message is inferable from the name and from the pointer to gmail_get_message, but there is no explicit when-to-use/when-not guidance or mention of gmail_search as an alternative entry point.

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