javalens-mcp

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes key behaviors: it returns a list with locations, uses zero-based coordinates (important for parameter interpretation), and has a prerequisite ('Requires load_project'). However, it doesn't mention potential limitations like performance impacts, error conditions, or whether results are cached, leaving some behavioral aspects unspecified.

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 clear sections (purpose, usage, output, important note, prerequisite). It's appropriately sized at 5 sentences, with each sentence adding value. The front-loaded purpose statement is clear, though the formatting with all-caps sections could be slightly refined for better readability.

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 (4 parameters, no output schema, no annotations), the description is reasonably complete. It covers purpose, usage, output format, coordinate system, and prerequisites. However, without an output schema, it could benefit from more detail on the return structure (e.g., format of 'locations'), and it doesn't address potential edge cases or error scenarios.

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?

The schema description coverage is 100%, so the schema already documents all parameters. The description adds value by explaining that coordinates are 'ZERO-BASED,' which clarifies the semantics of 'line' and 'column' parameters beyond what the schema states. However, it doesn't provide additional context for 'maxResults' or 'filePath' beyond the schema's descriptions.

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: 'Find implementations of an interface or extensions of a class.' It specifies the verb ('Find'), the resource ('implementations/extensions'), and distinguishes it from siblings like 'find_references' or 'get_type_hierarchy' by focusing on implementation/extension relationships rather than general references or hierarchy navigation.

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 provides explicit usage guidelines: 'Position on a type (interface or class), find all implementors/subclasses' and 'Requires load_project to be called first.' It clearly states when to use it (position on a type) and includes a prerequisite, distinguishing it from tools like 'analyze_type' or 'get_type_hierarchy' that might not require project loading or specific positioning.

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