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

Annotations already cover read-only, idempotency and closed-world, yet the description adds genuinely non-obvious behavior: retrieval is deterministic graph traversal from Schedulable.itemRef outward, and the LLM only renders rather than deciding what to fetch. That tells the agent results are reproducible and safe to re-request, which annotations alone would not convey.

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 tightly packed sentences, front-loaded with the deliverable and followed by the retrieval guarantee. The trailing "Read-only." restates the readOnlyHint annotation, a minor redundancy, but nothing else is padding.

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?

An output schema exists, so return values need no explanation, and the description covers what matters for correct invocation: payload contents, determinism, and the optional LLM summary. Only the missing sibling routing keeps it short of full completeness.

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% for all four parameters, so the baseline is 3. The description only gestures at includeSummary via "optional 1-paragraph summary" and adds nothing about eventId, userDayKey, or the cache-bypass semantics beyond what the schema documents.

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?

"Return a structured meeting prep brief — linked work, attendees, context, open threads" gives a specific verb plus an enumerated payload, so an agent can tell this apart from calendar.read or schedule.read without inspecting either schema. Scope and output shape are stated in the first clause.

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?

The name and payload list imply the 'preparing for a meeting' scenario, but the description never says when to choose this over calendar.read, schedule.read, or workspace.search, nor any precondition such as needing a valid eventId first. Usage is inferable rather than stated.

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