gmail_get_thread_summary

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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower; the description still adds real value beyond them by disclosing the HTML-to-Markdown conversion, the pagination behavior, and the critical prompt-injection warning that thread content is untrusted. It omits what 'summary' means relative to the tool name, which keeps it below a 5.

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?

Three short sentences, front-loaded with the core action, and the security warning is placed last where it is most visible. Nothing is redundant.

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?

No output schema exists, and the description covers the transformation, pagination, and trust posture, which is nearly everything needed to call it safely. The only gap is that the tool is named 'thread_summary' yet the description never says what makes the return a summary rather than a full thread dump.

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%, so the four parameters are already documented in-schema; the description only gestures at pagination without adding syntax or defaults. Baseline 3 applies where the schema does the heavy lifting.

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?

Specific verb and resource ('Fetches a Gmail conversation') plus the transformation it applies ('converts HTML bodies to safe Markdown'). It doesn't name or contrast any sibling (e.g. gmail_get_message_details, gmail_get_attachment), so a 4 rather than 5.

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?

Pagination is mentioned ('Supports pagination for long threads'), which implies the use case for part of the schema, but there is no explicit when-to-use/when-not guidance and no routing to alternatives such as gmail_search_messages or gmail_get_message_details.

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