update_draft

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

With no annotations, the description carries the full behavioral burden and does so well: it discloses partial-update semantics, the critical UID-reassignment on every update, removal of the old version, and the fact that no email is sent. It omits permission/auth requirements and error behavior for a stale UID, which is the only notable gap.

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?

Four short sentences, all load-bearing: purpose first, then update semantics, then the UID lifecycle warning marked IMPORTANT, then the non-send guarantee. No 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?

For a 9-parameter mutation tool with no annotations and no output schema, the description covers the behaviors an agent most needs: merge semantics, UID churn, and the no-send guarantee. The remaining omissions (authorization, stale UID handling) are minor but real.

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 coverage is 100%, so the baseline is 3, but the description adds value beyond the schema by clarifying that untouched fields such as recipients, subject, reply threading, and attachments are preserved, and by warning that the uid must come from the most recent create/update result.

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 verb (revise) plus resource (existing draft in the Drafts folder), immediately distinguishing it from create_draft and create_reply_draft among its siblings. An agent can tell it is a mutation of an existing draft without opening the schema.

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?

Clearly establishes context: it operates on an existing draft and only touches fields you pass, implying that new drafts should go through create_draft. It does not explicitly name the alternative tools or state preconditions (e.g. draft must exist), so it stops short of full routing guidance.

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