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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered; the description adds the substantive behavioral fact that the returned files form a complete, validated, deploy-ready app rather than a partial scaffold. It does not discuss file counts, size, or template-vs-app file differences, but the output schema covers the return structure.

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?

Two sentences, front-loaded with the return value and its guarantees, followed by the action to take. Nothing is redundant or padded.

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 read-only, two-parameter fetch with a full schema and an output schema, the agent has everything needed: where ids come from (schema), what comes back (description plus output schema), and what to do next. Nothing essential is missing.

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 both parameters (id and name) are fully documented in the schema, including the example id and the effect of name on title and letter icon. The description adds no further parameter-level meaning, so the baseline 3 applies.

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 ("Returns the source files of one starter template"), specifies the return shape ({path: content}), and characterizes the artifact as a complete app that passes check_app and is deployable. This clearly separates it from list_templates, which only enumerates template ids.

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?

The description gives a clear usage pattern: fetch a template as a starting point, then "change the files to build what the person asked for," implying the modify→check→deploy workflow via the named check_app/deploy_app siblings. It stops short of explicit exclusions, such as when to use get_app_source or get_app for an existing app instead.

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