Build Mail Digest

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

No annotations are provided, so the description carries the full burden. It discloses that the tool summarizes by multiple criteria, implying read-only aggregation, but does not explicitly state it does not modify messages or mention authentication requirements/rate limits. Adequate but not rich behavioral detail.

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: first is the core definition, second provides useful multilingual intents for Chinese-language agents. No filler, appropriately sized.

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 tool with 2 well-described params and no output schema, the description covers purpose and criteria sufficiently. It lacks explicit return format, but 'summarize' implies a text digest, which is reasonable given the tool's simplicity.

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 has 100% coverage with clear descriptions (focus, hours). The description adds context about digest dimensions (urgency, sender domain, attachments) not captured in schema, enriching the agent's understanding of what the summary contains.

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?

Description uses specific verb 'Summarize' with resource 'recent mail' and lists grouping dimensions (urgency, sender domain, read state, flags, attachments), clearly distinguishing it from low-level mail listing/searching siblings. Chinese intent examples reinforce the exact user-facing purpose.

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?

States what it does (summarize recent mail) and includes Chinese intents like '查看重要未读邮件' (view important unread mail), providing clear usage context. It does not explicitly name alternatives or exclusions, but the summarization function is distinct from search/list siblings.

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