threads_awaiting_reply

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

Annotations declare readOnlyHint=true, and the description is consistent. The description adds valuable behavioral detail beyond the annotation: it groups by thread_id, drops messages carrying List-Unsubscribe headers, and warns that older rows may lack thread_id/list_unsubscribe unless a backfill is run. This gives the agent a realistic picture of data completeness and filtering behavior.

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 sentences with no filler: the main action is front-loaded, the second sentence explains the core filtering logic, and the third is a compact operational note about the backfill command. Every sentence 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?

Given there are no parameters and an output schema exists, the description fully covers what an agent needs to decide whether to call the tool and what to expect: source, unread/active filter, newsletter exclusion, and a data-quality caveat. Nothing critical 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?

The input schema has no parameters, so there are no call arguments to document and schema coverage is effectively 100%. The description mentions internal fields like thread_id and list_unsubscribe, but those are implementation details rather than invocation parameters, so the baseline score for zero parameters 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 ('List'), a clear resource ('unread Gmail threads'), and the intended outcome ('that look like they need a reply'). The second sentence sharpens this by explaining that it groups by thread_id and drops List-Unsubscribe-bearing newsletters, making the tool's niche unambiguous.

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?

Provides clear operational context: the tool is for triaging active unread threads that plausibly need a reply, and explicitly excludes newsletter-style List-Unsubscribe messages. It also gives a concrete data prerequisite with the backfill command. It does not name alternatives or state explicit when-not-to-use cases, but no sibling tool appears to cover this same niche.

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