Frida Agent MCP

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 the behavioral sequence (kill, relaunch, connect, inject) and mentions using send() for data return, which adds useful context. However, it lacks details on permissions, error handling, or side effects, leaving some behavioral aspects unclear.

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 well-structured with a purpose statement, usage guidelines, and parameter explanations in separate sections. It is appropriately sized with no redundant information, though the parameter details could be slightly more concise.

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 complexity of the tool (combining multiple operations) and no annotations, the description covers purpose, usage, and parameters effectively. With an output schema present, it doesn't need to explain return values, making it reasonably complete for the context.

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 0%, so the description must compensate. It explains all three parameters: 'package' as the app package name with an example, 'script' as Frida JavaScript code with usage note, and 'script_file' as a path for large scripts. This adds significant meaning beyond the bare schema, though it could provide more on format or constraints.

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 specific action sequence: kill app, relaunch, connect, and inject script. It distinguishes from siblings by combining multiple operations (kill_app, launch_app, connect, execute) into one tool, making the purpose explicit and differentiated.

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?

It explicitly states when to use this tool: 'when you need to hook early initialization (e.g. onCreate, static initializers).' It also mentions the equivalent sibling tools (kill_app, launch_app, connect, execute), providing clear alternatives and context for usage.

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