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

Annotations already declare write, idempotent, non-destructive. The description still adds real context: the resulting version is immutable and a repeat call returns the same version, which confirms and sharpens the idempotency contract. It does not cover failure modes or return payload.

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 short sentences, front-loaded with the action, then the precondition, then the idempotency note. No filler or repetition.

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?

With no output schema, the description does not say what the call returns or how failures surface, but it does supply the workflow gating and the immutability/idempotency facts an agent needs. Adequate but not exhaustive for a state-mutating tool.

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 both required parameters, so the schema carries the load. The description adds no meaning about template_id or message_id beyond what is already documented, making the baseline 3 appropriate.

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 and resource: saving the current message draft as the next immutable template version. However, it never distinguishes itself from close siblings like save_template_version or save_template, leaving the agent to infer the difference from names alone.

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?

Gives an explicit precondition: call only after get_template shows the message succeeded and chat.current_draft is true. That is a strong gating condition, though it offers no exclusion guidance against the similar save_* siblings.

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