# AI use cases for MCP Slim Guard (lennney/mcp-slim-guard)

Repo: [lennney/mcp-slim-guard](https://github.com/lennney/mcp-slim-guard) | Use cases: 4 | Page: https://dedupedai.com/use-cases/lennney-mcp-slim-guard/

MCP Slim Guard is a TypeScript gateway that gives a host one guarded way to reach authorized upstream MCP tools, with schema-preserving compact modes and exact recovery of oversized results.

This file holds every use case of this repo. Each one starts with a "## " heading and ends with its URL.

- Give Codex a guarded, authorized MCP catalog: https://dedupedai.com/use-cases/lennney-mcp-slim-guard/guard-codex-mcp-catalog-native/
- Recover oversized MCP results without re-running calls: https://dedupedai.com/use-cases/lennney-mcp-slim-guard/recover-large-tool-results-exactly/
- Shrink first tool responses for Claude Code: https://dedupedai.com/use-cases/lennney-mcp-slim-guard/shrink-first-response-with-extreme-mode/
- Measure mode trade-offs on your own MCP setup: https://dedupedai.com/use-cases/lennney-mcp-slim-guard/benchmark-guard-modes-on-own-tools/

## How to give Codex a guarded, authorized MCP catalog with MCP Slim Guard

Repo: [lennney/mcp-slim-guard](https://github.com/lennney/mcp-slim-guard) | Difficulty: Intermediate | Time: 30 minutes | Basis: From the README

Route Codex through Slim Guard in Native mode so it sees authorized tools with full schemas.

**Who it is for:** A developer using Codex on a project with MCP servers who wants the normal tool catalog but with allow/deny checks and call validation in front of it.

**The problem:** Connecting Codex straight to upstream MCP servers gives no single place to enforce allow/deny rules or check arguments before the upstream is contacted.

**The outcome:** Codex lists only authorized original tool names with full schemas, and calls are validated before any upstream server is invoked.

### Steps

1. In the reviewed checkout, run `npm ci`, then `npm run build`, then `npm link`.
2. Change into your project directory and run `mcp-slim-guard init`, then `mcp-slim-guard validate`.
3. Edit `mcp-slim-guard.yml` so the `tools` allow and deny patterns match what Codex should reach.
4. Run `mcp-slim-guard plan --host codex` to review the host plan without changing host files.
5. Run `mcp-slim-guard verify --host codex`, then `mcp-slim-guard install --host codex --mode native`.

### Prompt to paste into your agent

```text
Use the lennney/mcp-slim-guard repo to set up Native mode for Codex in the project at <project-path>. Run the plan and verify commands from the README and report the planned host entry. Confirm that `mcp-slim-guard verify --host codex` reports a configured runtime before you apply the install.
```

### Caveat

The package is an alpha source candidate that is not on npm yet, and the README advises reviewing authorization patterns before using it with privileged tools.

Disclaimer: Third-party repos we don't own or vouch for. AI-generated use cases can be wrong: review everything and run at your own risk. Full text: https://dedupedai.com/disclaimer/

URL: https://dedupedai.com/use-cases/lennney-mcp-slim-guard/guard-codex-mcp-catalog-native/

## How to recover oversized MCP results without re-running calls with MCP Slim Guard

Repo: [lennney/mcp-slim-guard](https://github.com/lennney/mcp-slim-guard) | Difficulty: Intermediate | Time: 30 minutes | Basis: From the README

Use result_ref and read_result to pull exact pieces of a big tool response.

**Who it is for:** An agent operator whose host hits context limits when an upstream tool returns a very large result.

**The problem:** A large tool response floods the context window, and re-running the upstream call to see more of it may be costly or change the result.

**The outcome:** The host reads the exact stored snapshot in bounded fragments or by cursor, and the upstream tool is not invoked again.

### Steps

1. Run `mcp-slim-guard start` in the project so the default Compact mode is active.
2. Make the tool call through the host and note the `result_ref` in the first response.
3. Call `read_result` with a `query` to get up to three bounded local fragments.
4. Or call `read_result` without `query` and follow `next_cursor` to recover the exact snapshot. Do not combine `query` with `cursor`.

### Prompt to paste into your agent

```text
In the lennney/mcp-slim-guard setup at <project-path>, trigger a tool call that returns a large result and capture its result_ref. Use read_result with a query to retrieve matching fragments, and confirm the fragments come from the same snapshot without a second upstream invocation.
```

### Caveat

Recovery only works on responses that need recoverable delivery, and the README does not describe the size threshold that triggers it.

Disclaimer: Third-party repos we don't own or vouch for. AI-generated use cases can be wrong: review everything and run at your own risk. Full text: https://dedupedai.com/disclaimer/

URL: https://dedupedai.com/use-cases/lennney-mcp-slim-guard/recover-large-tool-results-exactly/

## How to shrink first tool responses for Claude Code with MCP Slim Guard

Repo: [lennney/mcp-slim-guard](https://github.com/lennney/mcp-slim-guard) | Difficulty: Intermediate | Time: 30 minutes | Basis: From the README

Use Extreme mode so large results arrive as a smaller first delivery that stays recoverable.

**Who it is for:** A Claude Code user working in a context-sensitive session where big MCP results crowd out the rest of the conversation.

**The problem:** Full-size tool results fill the context quickly, leaving little room for the actual task.

**The outcome:** Large results come back as a shorter first delivery with a result_ref, and the exact response can still be read back.

### Steps

1. Run `mcp-slim-guard plan --host claude-code --mode extreme` to review the planned host entry without changing files.
2. Run `mcp-slim-guard install --host claude-code --mode extreme` after reviewing the plan. (inferred, check the README)
3. Start a session that makes a tool call with a large result and check that the first response includes a `result_ref`.
4. Use `read_result` to fetch the rest of the exact response when the task needs it.

### Prompt to paste into your agent

```text
For the lennney/mcp-slim-guard project at <project-path>, produce the Claude Code Extreme mode plan and show the host entry it would write. Then run one large tool call and confirm the first response is shorter than the exact response and includes a result_ref.
```

### Caveat

The README says Extreme only shortens a response when the first delivery is at least half the size of the exact response, so small results pass through unchanged.

Disclaimer: Third-party repos we don't own or vouch for. AI-generated use cases can be wrong: review everything and run at your own risk. Full text: https://dedupedai.com/disclaimer/

URL: https://dedupedai.com/use-cases/lennney-mcp-slim-guard/shrink-first-response-with-extreme-mode/

## How to measure mode trade-offs on your own MCP setup with MCP Slim Guard

Repo: [lennney/mcp-slim-guard](https://github.com/lennney/mcp-slim-guard) | Difficulty: Advanced | Time: 45 minutes | Basis: From the README

Run the bundled benchmarks and stress fixture to compare Native, Compact, and Extreme.

**Who it is for:** A developer or researcher deciding which Slim Guard mode suits a large tool catalog and wants local numbers instead of published claims.

**The problem:** Choosing a mode without measurements means guessing how much context each mode saves on a real catalog.

**The outcome:** Locally generated reports for the task comparison, compression, and stress fixtures that reflect the current build.

### Steps

1. Run `npm ci`, then `npm run build`, in the reviewed checkout.
2. Run `npm run bench:task`, then `npm run bench:compression`.
3. Run `npm run bench:stress` to exercise the 100-tool and 8,000-row fixture.
4. Run `npm run bench:compression:verify` and read the mode-specific reports it generates.

### Prompt to paste into your agent

```text
In the lennney/mcp-slim-guard repo, run the build and the bench:task, bench:compression, and bench:stress scripts, then summarize the generated reports by mode. Verify that the report is produced locally and that you do not cite the older alpha figures as results.
```

### Caveat

The README says the benchmark reports are generated locally and older alpha figures should not be treated as claims for this product line.

Disclaimer: Third-party repos we don't own or vouch for. AI-generated use cases can be wrong: review everything and run at your own risk. Full text: https://dedupedai.com/disclaimer/

URL: https://dedupedai.com/use-cases/lennney-mcp-slim-guard/benchmark-guard-modes-on-own-tools/