sourcemap-retrace-mcp

by vola-trebla

Overview Schema Source Related Servers Discussions Admin

TypeScript

Local

retrieve_code_context

Fetch surrounding source lines for a given mapped error position to view the original code context.

Instructions

Show the original source code lines surrounding a mapped error location.

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": {
      "originalFile": "<originalFile>",
      "line": "<line>"
    },
    "name": "retrieve_code_context"
  }
}

Input Schema

Name	Required	Description
`line`	Yes	1-based line number in the original source
`column`	No	0-based column number
`contextLines`	No	Number of lines to show before and after the target line
`originalFile`	Yes	Absolute path to the original TypeScript source file

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.2.0Aug 5, 2026

TDQS

A4/5.0

Behavior3/5

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

With no annotations provided, the description carries the full burden. The verb 'Show' indicates a read-only operation, and 'surrounding' clarifies context scope. However, it omits details such as file system prerequisites, handling of invalid paths, or return format, leaving some behavioral ambiguity.

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, front-loaded sentence with no filler. Every word contributes meaning, achieving maximum clarity with minimal length.

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

Completeness4/5

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

For a simple read tool with fully documented parameters and no output schema, the description sufficiently explains what the tool does and what it returns (source lines). It is complete for the tool's complexity, though not as rich as a 5 would require.

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?

Schema description coverage is 100%, so the baseline is 3. The description adds some context by linking 'mapped error location' to the parameters, but it does not provide additional semantic detail beyond what the schema already documents.

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 uses a specific verb ('Show') and resource ('original source code lines') with a clear scope ('surrounding a mapped error location'). It distinguishes this tool from siblings like retrace_stack (which maps stack traces) and audit_sourcemap_match (which validates sourcemap integrity).

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

Usage Guidelines4/5

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

The description clearly conveys when to use the tool: when you have a mapped error location and need surrounding source lines. It does not explicitly mention alternatives or exclusions, so it stops short of a 5, but the use case is well implied.

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

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