gmail get thread

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the bar is lower, yet the description still discloses genuinely non-obvious behavior: bodies are capped per message AND by a shared thread-wide budget, after which later bodies come back empty and flagged truncated. That is exactly the kind of silent-degradation detail an agent needs. It stops short of describing attachment handling or pagination/auth requirements.

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?

Two sentences, zero filler: the first states what is returned, the second front-loads the truncation caveat. Nothing is repeated from the schema or annotations.

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?

An output schema exists, so return-value documentation is not required, and the description covers the one behavioral trap (body budget exhaustion). Minor gaps remain around whether non-body metadata such as attachments or labels is included, but nothing essential to a correct call 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 must carry the load and it does for max_body_chars: it explains the per-message cap and the shared thread-wide total, which is more than the schema's bare integer type and default. thread_id is left entirely undefined, though its meaning is largely self-evident.

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 — 'Get every message in a thread' — plus the payload shape (headers and plain-text bodies). An agent can distinguish it from gmail_get_message by the word 'thread', but the description never names that sibling, so differentiation is inferred rather than stated.

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?

No explicit when-to-use or when-not-to-use statement, and no alternative tool is named. Usage is only implied by the scope word 'thread' (versus per-message retrieval) and by the truncation note, which hints at the cost tradeoff of large threads.

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