build_corpus

SERVERTrace SOURCEnikolai-vysotskyi/trace-mcp

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/nikolai-vysotskyi-trace-mcp/build-corpus.md

WHAT IT DOES

What build_corpus does on Trace

AI agents use build_corpus to create or update resources in Trace, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Trace environment.

RISK

Why build_corpus is rated Medium

The tool writes a new persistent corpus file to disk and mutates the corpora store. This is a reversible write operation (the corpus can be deleted), not destructive. The blast radius is medium since it writes persistent data to disk that affects future LLM queries, but does not execute code or delete anything.

From the tool's definition Pack a slice of project context into a persistent corpus on disk... Mutates the corpora store; returns JSON with the saved manifest.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs build_corpus safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Trace, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For build_corpus, this is the rule to start with:

build_corpus Rate-limited

build_corpus stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "build_corpus": {
      "limits": [
        {
          "counter": "build_corpus_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Trace, apply this rule, and every build_corpus call is checked against it from then on.

FAQ

Questions about build_corpus

What does the build_corpus tool do? +

Pack a slice of project context into a persistent corpus on disk so future query_corpus calls can prime an LLM with the same snapshot without re-running the pack pipeline. Mutates the corpora store; returns JSON with the saved manifest. Pair with query_corpus for. It is categorised as a Write tool in the Trace MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on build_corpus? +

Register the Trace MCP server in PolicyLayer and add a rule for build_corpus: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Trace. Nothing to install.

What risk level is build_corpus? +

build_corpus is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit build_corpus? +

Yes. Add a rate_limit block to the build_corpus rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block build_corpus completely? +

Set action: deny in the PolicyLayer policy for build_corpus. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides build_corpus? +

build_corpus is provided by the Trace MCP server (nikolai-vysotskyi/trace-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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