feat(grok): support MCP config

[janburzinski]

Description

• add mcp support for grok
• add grok .grok/config.toml adapter
• support stdio and http mcp servers

Screenshot/Recording (if applicable)

https://cap.link/mhbpmbxbettbdvs

Checklist

• I kept this PR small and focused
• I ran a self-review before opening this PR
• I ran the relevant local checks or explained why not
• I updated docs when behavior or setup changed
• I added or updated tests when behavior changed, or explained why not
• I only added comments where the logic is not obvious
• I used Conventional Commits for commit
  messages and, when possible, the PR title

[greptile-apps]

Greptile Summary

This PR adds MCP (Model Context Protocol) server support to the Grok AI CLI plugin by implementing a grokMcpAdapter that reads and writes Grok's .grok/config.toml TOML config format, and wires it into the plugin's capability declaration.

• grokMcpAdapter in mcp.ts handles both stdio and HTTP transports; unlike the Codex adapter it keeps HTTP headers under their canonical key (no rename to http_headers) and injects enabled: true by default on write, matching the grok mcp add CLI behavior.
• grok/index.ts declares the mcp capability with scope: 'global' and registers the adapter as the provider — consistent with how all other agent plugins expose MCP support.
• Six new test cases in mcp.test.ts cover stdio write, HTTP write, enabled: false preservation, read, round-trip, and server removal.

Confidence Score: 5/5

Safe to merge — changes are additive and isolated to a new adapter function with no modifications to existing adapters or shared infrastructure.

The adapter faithfully mirrors the pattern established by codexMcpAdapter with intentional, well-documented deviations (no header renaming, default enabled flag). The test suite exercises every public code path including edge cases (explicit disabled, round-trip, multi-server removal), and the grok/index.ts changes are purely declarative additions.

No files require special attention.

Important Files Changed

Filename	Overview
packages/core/src/agents/plugins/helpers/mcp.ts	Adds grokMcpAdapter following the established Codex pattern, with intentional differences: headers stay under headers (not renamed to http_headers) and enabled: true is injected by default on write. Logic is correct and consistent.
packages/plugins/src/agents/impl/grok/index.ts	Wires up MCP capability declaration (scope: global, stdio + http transports) and registers grokMcpAdapter() as the provider — consistent with how other agent plugins expose MCP support.
packages/core/src/agents/plugins/helpers/mcp.test.ts	Adds 6 targeted test cases for grokMcpAdapter covering stdio write, HTTP write, enabled=false preservation, round-trip read, remove, and existing-config preservation. Coverage is thorough.

Sequence Diagram

%%{init: {'theme': 'neutral'}}%%
sequenceDiagram
    participant UI as Emdash UI
    participant Plugin as grok/index.ts
    participant Adapter as grokMcpAdapter
    participant FS as ~/.grok/config.toml

    UI->>Plugin: writeServers(servers)
    Plugin->>Adapter: writeServers(fs, servers)
    Adapter->>FS: read existing TOML
    FS-->>Adapter: raw content (or empty)
    Note over Adapter: toNative(s):<br/>delete name/transport/type<br/>set enabled=true if not boolean<br/>keep headers as-is
    Adapter->>FS: write merged TOML

    UI->>Plugin: readServers()
    Plugin->>Adapter: readServers(fs)
    Adapter->>FS: read TOML
    FS-->>Adapter: raw content
    Note over Adapter: fromNative(name, raw):<br/>isHttp = url present && command absent<br/>if HTTP: set transport='http', type='http'
    Adapter-->>UI: McpServerRegistration[]

    UI->>Plugin: removeServer(name)
    Plugin->>Adapter: removeServer(fs, name)
    Adapter->>FS: read → filter → write TOML

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%%{init: {'theme': 'base', 'themeVariables': {"darkMode": true, "background": "#0d1117", "primaryColor": "#21262d", "primaryTextColor": "#e6edf3", "primaryBorderColor": "#8b949e", "lineColor": "#8b949e", "textColor": "#e6edf3", "edgeLabelBackground": "#161b22", "actorBkg": "#21262d", "actorBorder": "#8b949e", "actorTextColor": "#e6edf3", "actorLineColor": "#8b949e", "signalColor": "#8b949e", "signalTextColor": "#e6edf3", "noteBkgColor": "#373320", "noteBorderColor": "#d4a72c", "noteTextColor": "#f0e6c0", "labelBoxBkgColor": "#21262d", "labelBoxBorderColor": "#8b949e", "labelTextColor": "#e6edf3", "loopTextColor": "#e6edf3", "activationBkgColor": "#30363d", "activationBorderColor": "#8b949e"}}}%%
sequenceDiagram
    participant UI as Emdash UI
    participant Plugin as grok/index.ts
    participant Adapter as grokMcpAdapter
    participant FS as ~/.grok/config.toml

    UI->>Plugin: writeServers(servers)
    Plugin->>Adapter: writeServers(fs, servers)
    Adapter->>FS: read existing TOML
    FS-->>Adapter: raw content (or empty)
    Note over Adapter: toNative(s):<br/>delete name/transport/type<br/>set enabled=true if not boolean<br/>keep headers as-is
    Adapter->>FS: write merged TOML

    UI->>Plugin: readServers()
    Plugin->>Adapter: readServers(fs)
    Adapter->>FS: read TOML
    FS-->>Adapter: raw content
    Note over Adapter: fromNative(name, raw):<br/>isHttp = url present && command absent<br/>if HTTP: set transport='http', type='http'
    Adapter-->>UI: McpServerRegistration[]

    UI->>Plugin: removeServer(name)
    Plugin->>Adapter: removeServer(fs, name)
    Adapter->>FS: read → filter → write TOML

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_{Reviews (1): Last reviewed commit: "fix(mcp): ignore default enabled in merg..." | Re-trigger Greptile}

[arnestrickmann]

thanks for the addition!