TypeScript AST MCP Server

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find_implementations

Finds classes implementing a given interface by checking explicit 'implements' clauses and structural member compatibility via the TypeScript type checker.

Instructions

Finds classes that implement a specified interface - explicit 'implements' plus structural matches, checked by the TypeScript type checker (member types and call signatures, not just names)

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "path": "<path>",
      "interface": "<interface>"
    },
    "name": "find_implementations"
  }
}

Input Schema

Name	Required	Description	Default
`path`	Yes	Absolute path to the file or directory to search
`interface`	Yes	Name of the interface to check against

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Aug 1, 2026

TDQS

A3.9/5.0

Behavior4/5

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

Since no annotations are provided, the description carries the disclosure burden. It discloses the TypeScript type checker usage and that it checks member types and call signatures, not just names, which is a valuable behavioral trait. However, it does not explicitly mention side effects, error conditions, or read-only nature, though 'finds' implies a non-mutating operation.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single sentence that front-loads the core action and then adds relevant details about structural matching and type checking. Each clause contributes necessary information, and it avoids redundancy or excessive length.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description thoroughly explains the tool's approach and purpose, but it does not describe the return format (e.g., list of classes, file locations) or any prerequisites such as a valid TypeScript project. Since there is no output schema, these omissions leave gaps in what an agent can expect from the tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already describes both parameters with 100% coverage. The description adds minimal per-parameter meaning beyond implying that the interface is used for type checking, which is already evident from the tool's purpose. Thus, the baseline of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool finds classes implementing a specified interface, with specific details on explicit 'implements' and structural matches. This makes it distinct from sibling tools like find_usages or get_type_definition, which serve different purposes.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies its usage when the agent needs to discover classes that implement an interface, but it does not explicitly compare with alternatives or state when not to use it. There is no guidance on selection among sibling tools, so it only provides implied context.

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