build_fastapi_app

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

There are no annotations, so the description carries the full burden for behavioral transparency. It mentions scaffolding a codebase, which implies side effects, but it does not disclose whether the tool overwrites existing files in the output directory, requires network access, validates the YAML, or has any other side effects. This is a significant gap for a code generation tool.

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?

The description is a single concise sentence (10 words) that front-loads the key action and outcome. Every word earns its place, with no redundancy or fluff.

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 tool that creates a complete codebase, the description is too thin. It lacks critical context such as whether the output directory will be created or overwritten, what the generated code includes, error behaviors, or prerequisites. The schema covers parameters but not the tool's overall behavior, making the description insufficient for a complex operation.

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%, with both parameters having descriptive text in the schema. The description adds minimal meaning beyond that, only restating that the YAML is an architecture definition. It does not explain the SystemArchitecture schema or clarify any subtle behaviors, so the baseline of 3 is 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?

The description clearly states the tool's function with a specific verb 'scaffolds' and a specific resource ('complete FastAPI codebase') and input ('YAML architecture definition'). It is not a tautology and gives a clear purpose, though there are no sibling tools to differentiate from, so it doesn't mention alternatives.

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 implies usage: use this when you have a YAML architecture definition and want a FastAPI codebase. However, it provides no explicit when-to-use guidance, no exclusions, and no alternative tools to consider, so it only meets the baseline for implied usage.

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