Compose template

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

Adds value beyond annotations: hero image default behavior, credit charge, auth scope, return fields. No contradiction with annotations (destructiveHint false, openWorldHint false).

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 front-loaded sentences: purpose, side-effect, usage guidance. No fluff; every sentence earns its place.

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?

Covers main workflow, return value, credits, auth. Missing: parameter explanations for most optional fields, error conditions. Adequate but not comprehensive for a 9-param tool without output schema.

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 11% (only prompt has description). Description clarifies includeHeroImage and prompt, but 7 of 9 parameters (key, mode, name, model, themeId, category, starterShellId) remain undocumented. Needs more parameter-level detail.

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?

Clearly states verb ('Compose'), resource ('new email from a natural-language brief'), and distinguishes from sibling with 'Prefer this over create_template when the operator gave a brief.'

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?

Explicitly says when to use (operator gave a brief), mentions credits and auth requirement. Could add when not to use, but the guidance is clear.

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