outlook_changes_since

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

Discloses key behaviors: fallback window to avoid historical items, independent tokens for each resource, auto-resync on 410 errors, and specifics about return fields (urgent_flagged, by_sender, calendar quirks). Adds value beyond readOnlyHint annotation.

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?

Description is detailed but well-organized with paragraphs and examples. Every sentence adds value, though slightly longer than minimal.

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?

Despite no output schema, the description thoroughly explains return fields and edge cases (410 errors, resync, calendar quirks). Covers all necessary context for effective use.

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?

With 0% schema coverage, the description fully explains both parameters: delta_tokens (object from prior response, independent per resource) and fallback_window_hours (default 24, purpose of filtering historical items).

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 it provides a 'structured digest across mail, events, and contacts' and distinguishes from sibling delta tools which return 'raw item lists or per-resource control'.

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 recommends use for 'recurring agent loops' and gives concrete usage scenarios: 'morning brief, hourly inbox sweep'. It explains when to use alternatives and provides a clear example of first call vs subsequent calls with delta_tokens.

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