find_newsletters

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

With no annotations, the description carries the full burden and does so well: it declares the tool read-only, discloses the scan bound (default 500, max 2000 via the schema), and warns that sender names and subjects are untrusted email content that must never be treated as instructions. It omits cost/latency implications of scanning up to 2000 messages and any failure behavior, which keeps it short of 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?

Three tight sentences: behavior and ordering first, the downstream action second, the security caveat last. Every sentence carries distinct information with no redundancy or filler.

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?

No output schema exists, and the description compensates by describing the result shape (sender grouping, unsubscribe method, sampleMessageId) and the untrusted-content wrapping. It is nearly complete for a four-optional-parameter read tool, though it could say more about scan cost or result limits.

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 the schema already explains folderId, maxMessages, excludeDomains, and includeNoUnsubscribe. The description adds workflow meaning by referencing sampleMessageId (an output field not in the input schema) but does not otherwise enrich parameter interpretation beyond what the schema provides.

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?

States a specific multi-step operation: scan recent messages in a folder, group by sender, and report which senders are mailing lists via List-Unsubscribe headers, ordered most-frequent-first. This is clearly distinguishable from siblings like list_messages and search_messages, which enumerate or filter messages rather than aggregate by sender.

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?

Implies the workflow explicitly by telling the agent to pass a result's sampleMessageId to unsubscribe, which routes it to the correct sibling tool. It also names the default folder (inbox). It does not explicitly state when to prefer list_messages or search_messages instead, so it falls short of full when/when-not guidance.

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