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

Annotations already declare destructiveHint=true and idempotentHint=false, and the description adds real value on top: it says main.film is replaced, that components are added to the project, and that a rule-breaking slot aborts with the slot named. It stops short of saying whether a failed call partially applies or what the success return looks like.

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?

Purpose is front-loaded in the first sentence and the remaining sentences cover validation, side effects, failure recovery, and follow-up steps without padding. The branchId restatement slightly duplicates the schema, a minor redundancy in an otherwise tight definition.

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 destructive, four-parameter tool with no output schema, the description covers side effects, error semantics, and the verification workflow. It omits what a successful call returns and whether long-running jobs are involved, which would fully close the loop.

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 meaning beyond it: slots must be JSON text matching read_template's shape and carrying this project's Asset IDs. The 'branchId null means the current version' sentence largely duplicates the schema, but the Asset-ID constraint is genuinely new information.

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 with scope: 'Build the whole film from a template', and the body clarifies the mechanics (validates slots, adds components, replaces main.film). This distinguishes it cleanly from siblings like replace_film, patch_film, and scaffold_component without needing 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?

Gives an explicit workflow: read_template supplies the slot shape, preview_frame verifies the result, patch_film adjusts it, and the failure mode tells the agent to fix the offending slot and re-call. It never explicitly excludes alternatives (e.g. replace_film) or states preconditions, so it falls just short of a 5.

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