Daily digest across all inboxes

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is conveyed structurally. The description adds meaningful behavior beyond that: the default 24h window, all-accounts default, the calendar-access gating, and the instruction to summarize per account. It does not discuss result size limits, truncation, or performance across many accounts, keeping 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?

The return contents are front-loaded in a single descriptive sentence, followed by usage triggers and a final summarization instruction. Every clause carries information, though the enumeration is dense and could be slightly tighter.

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 multi-source aggregator with no output schema, the description usefully enumerates the returned sections and the default windows, which is what an agent needs to decide to call it. Gaps remain around output shape, ordering, and behavior when some accounts lack calendar access, but overall it is complete enough for correct invocation.

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 all five parameters are already documented in the schema. The description restates a few of them (default last 24h, calendar inclusion, per-account scoping) but adds no syntax or format detail beyond the schema, which is the expected baseline when the schema does the work.

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 names a specific operation (one aggregated digest call) and enumerates exactly what it returns: unread counts, new personal mail, newsletter/notification counts, conversations needing a reply, and today's calendar events. It clearly distinguishes itself from narrower siblings like inbox_summary, needs_reply, find_newsletters, and search_emails by being the cross-account 'everything today' view.

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?

It gives concrete trigger phrases ('morning briefing', 'catch me up', 'what happened since yesterday') and states the default scope, which is strong positive guidance. It does not, however, say when NOT to use it or explicitly point to the narrower sibling tools for single-purpose lookups, so an agent must infer those exclusions.

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