get_follow_up_candidates

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

No annotations provided, so description carries full burden. It describes the tool as returning threads (read operation), but does not mention that the syncBefore parameter can mutate the local mailbox index. This side effect should be disclosed.

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?

The description is extremely concise with three sentences, each serving a distinct purpose: stating function, giving use cases, and suggesting an alternative. No wasted words.

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 the simplicity of the tool and full schema coverage, the description is largely complete. It covers purpose, usage, and alternatives. The only missing element is explicit mention of side effects from syncBefore, but overall it is sufficient for selection and basic understanding.

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 baseline is 3. The description adds context by mentioning 'age' and 'pending-on state', but does not elaborate on other parameters like limit and syncBefore beyond what the schema already covers.

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?

The description clearly states the tool returns threads overdue for follow-up based on age and pending-on state. It distinguishes it from the sibling get_actionable_threads by specifying the exact condition (outbound without reply or stale inbound).

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?

Explicitly says when to use it: for outbound messages without reply or stale inbound threads. Also provides a clear alternative: prefer get_actionable_threads for threads where someone is waiting on you.

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