Analyze an existing app codebase

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

No annotations are provided, so the description carries the full burden. It describes what the tool detects but does not explicitly state whether it is read-only or has any side effects. The name 'analyze' implies non-destructive behavior, but the description lacks an explicit guarantee. It does add the context that it complements source reading, which is useful, but does not cover all safety concerns.

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 concise, with three sentences that are all purposeful. It front-loads the purpose, lists detected items, gives usage guidance, and adds a limitation. No redundant information, well-structured for quick reading.

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?

Given the tool's moderate complexity and lack of output schema, the description adequately covers what the tool does and when to use it. It explains the scope (detects various aspects) and provides a limitation (does not replace reading source). Minor gap: it does not describe the output format or whether the analysis is returned as a report, but for a single-parameter tool with no output schema, the description is sufficiently complete.

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 one parameter (appPath) clearly described as the absolute path to the app's root folder. The description does not add additional parameter-specific details, so it earns the baseline score of 3. No extra semantics are provided beyond the schema.

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 purpose with a specific verb ('understand an existing app') and resource (app codebase). It enumerates what it detects (frameworks, language, dependencies, capabilities, folder structure, issues), and distinguishes it from siblings by positioning it as the FIRST tool to use for existing apps. This differentiates it from tools like import_app, test_app, and suggest_improvements.

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 explicitly states when to use it: 'Use this FIRST when asked to understand, improve, fix or extend an app that already exists.' It also provides an exclusion by noting it complements but does not replace reading the actual source code. This gives clear context and alternative behavior.

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