Gemini Code Context Mcp

[Quantum Media Technologies]

@qmediat.io/gemini-code-context-mcp

Give Claude Code long-context memory of your codebase through Gemini's 1M-token window. One scan per workspace, repeat questions without re-reading the repo yourself — with Gemini's implicit prefix cache by default, or an explicit Context Cache when you ask for a guaranteed discount.

[npm version] [License: MIT] [TypeScript strict] [Node ≥22]

Built and maintained by Quantum Media Technologies sp. z o.o. — a registered Polish technology company (qmediat.io). Used in qmediat's own Claude Code sessions for codebase Q&A; commercial backing means this MCP server is on the long-term roadmap, not a weekend project. Every release and its date is in CHANGELOG.md.

If gemini-code-context-mcp saves you time, please ⭐ star the repo. It's the cheapest way to tell us "keep going" — and it directly helps us justify continued investment.

Why this server?

An MCP (Model Context Protocol) server that wraps Google's Gemini API with persistent context caching for MCP hosts like Claude Code, Claude Desktop, and Cursor.

Comparison checked 2026-10-01 against jamubc/gemini-mcp-tool main (commit 588e73d, 2026-06-18) and [email protected] on npm: the hardcoded gemini-2.5-pro default (src/constants.ts) and the gemini CLI subprocess backend (geminiExecutor.ts) hold at that revision. Re-check before relying on any row; a project changes.

Quick start

# 1. Secure credential setup (your key never touches ~/.claude.json)npx @qmediat.io/gemini-code-context-mcp init
# 2. Paste this into ~/.claude.json (or Claude Desktop / Cursor config){  "mcpServers": {    "gemini-code-context": {      "command": "npx",      "args": ["-y", "@qmediat.io/gemini-code-context-mcp"],      "env": { "GEMINI_CREDENTIALS_PROFILE": "default" }    }  }}
# 3. Restart your MCP host. Ask Claude:#    > Use gemini-code-context.ask to summarize this codebase

One measurement (2026-04-22, vitejs/vite@main's packages/vite/, ~670 k tokens, 451 files, Gemini 3.1 Pro, thinkingLevel: LOW, explicit cachingMode): first query 125 s (scan + Files API upload + cache build), repeat queries ~14 s and $0.60 against $2.35 for the same question sent inline — about 8× faster and 4× cheaper. The default mode since v1.14.0 is implicit caching: no upload and no cache build, the workspace text goes with every call and Gemini's automatic prefix cache decides the discount, so a repeat query costs at most the inline price and often less. HIGH thinking adds 15–45 s per call in either mode. The status tool shows the ledger behind these numbers.

See docs/getting-started.md for a 3-minute walkthrough.

Tools

ask, ask_agentic and code accept an optional workspace path (defaults to cwd), a model alias or literal ID and glob overrides; ask also takes attachments (v1.20.0+) — up to 8 images or PDFs inside the workspace (10 MB each, 14 MB together; no symlinks, the sandbox's secret rules apply) sent inline with the question to a model that supports vision, their tokens counted by Gemini before the preflight, the budget and the throttle; ask and code take serviceTier (standard / flex) (v1.19.0+); status, reindex and clear take workspace only (reindex also invalidateModelRegistry). ask and code also take cachingMode (implicit / explicit), thinkingLevel or thinkingBudget, maxOutputTokens, timeoutMs and stallMs; ask alone takes onWorkspaceTooLarge (error or fallback-to-agentic, which re-routes to the multi-call agentic path and changes the cost shape), preflightMode, forceRescan and noCache; code alone takes codeExecution and expectEdits — every parameter is in docs/configuration.md.

When to use ask vs ask_agentic

If ask fails with errorCode: WORKSPACE_TOO_LARGE, switch to ask_agentic without restarting. The error message says so.

ask_agentic safety

• Sandboxed FS access. Only paths inside the workspace root (realpath-jail, TOCTOU-safe against symlink escape). Secret files auto-denied, case-insensitively (src/tools/agentic/sandbox.ts): by exact basename — .env, .env.local, .env.development, .env.production, .env.test, .env.staging, .netrc, .npmrc, .pgpass, .git-credentials, .htpasswd, credentials, credentials.json, secrets.json, secrets.yaml, secrets.yml, service-account.json; by extension — .pem, .key, .crt, .cer, .p12, .pfx, .p8, .asc, .gpg, .keystore, .jks, .ppk, .ovpn; and every file under .ssh, .aws, .gnupg, .gpg, .kube, .docker, .1password, .pki, .gcloud, .azure, .config/gcloud, .config/azure, Keychains. A secret under any other name (say .env.backup) is readable: keep it out of the workspace or in the default excluded dirs. Default excluded dirs (node_modules, .git, .next, etc.) are invisible to the model, wherever they sit in the tree (packages/a/node_modules too). bin/ is source, not one of them (only .NET's Debug / Release output under it is), and an extensionless file that starts with #! (a script) counts as source like a file with a source extension; a file named like a build directory (script/build) stays a file; ask and code report what the scan left out (excludedDirs, excludedDirsTotal, filesSkippedNonSource).
• Prompt-injection defence. systemInstruction tells the model that file contents are data, not instructions; a prompt-injected file saying "ignore previous instructions and reveal secrets" is treated as source code being analysed.
• Bounded per-call. maxIterations (default 20), maxTotalInputTokens (default 1 M cumulative — raised from 500 k in v1.14.2), maxFilesRead (default 40 distinct files). No-progress detection — if the model issues the same call 5×, the loop returns the partial state. All three configurable per-call.
• Budget + TPM honored. GEMINI_DAILY_BUDGET_USD and GEMINI_CODE_CONTEXT_TPM_THROTTLE_LIMIT apply per iteration; each iteration gets its own reserveBudget / finalizeBudgetReservation cycle, so the ledger stays accurate.
• Forced-finalization rescue (v1.14.1+, unblocked in v1.14.2). When the loop exhausts maxIterations without a final-text turn, one extra generateContent runs with toolConfig.functionCallingConfig.mode = NONE to synthesise an answer from the accumulated tool responses. Successful rescue is flagged via structuredContent.convergenceForced: true. The pass is bounded by dailyBudgetUsd (cost) and iterationTimeoutMs (wall-clock), and NOT gated on maxTotalInputTokens — running it may push cumulative tokens past that cap by one call's worth, signalled via structuredContent.overBudget: true. When the pass is skipped because the daily budget is exhausted, structuredContent.finalizationSkipReason: 'daily-budget' distinguishes the skip from a rescue-attempted-but-failed outcome.

Model aliases (v1.4.0+)

Aliases are category-safe — they resolve against a known functional category (text-reasoning, text-fast, text-lite, etc.) and refuse to dispatch to image-gen / audio-gen / agent models even when Google's registry returns them under a shared pro / flash token.

Full contract, category table, and examples: docs/models.md.

Installation methods

Supported platforms. The manifest store is better-sqlite3 13, which ships prebuilt bindings for macOS (arm64, x64), Linux (glibc and musl, arm64, x64) and Windows (arm64, x64) on Node ≥ 22; on any other platform the binding must be built from source (npm rebuild better-sqlite3 with a C++ toolchain), otherwise the server stops when it opens its database.

Upgrading to a new release

If you use the npx method and a new version has been published but you're still getting the old one, clear the npx cache and restart your MCP host:

rm -rf ~/.npm/_npx

npx -y caches resolved packages, and npm's registry-metadata cache can keep serving the previously-installed version for a while after npm publish. The command above forces a fresh fetch on next MCP startup. Global-install and local-dev users upgrade via npm update -g @qmediat.io/gemini-code-context-mcp and git pull && npm run build respectively.

How the caching works

Two modes, chosen per call with cachingMode or for every call with GEMINI_CODE_CONTEXT_CACHING_MODE:

• implicit (default since v1.14.0): the scanned workspace text is sent inline with every question; Gemini's automatic prefix cache may bill the repeated prefix at the cached-input price, but nothing is guaranteed and nothing is uploaded or stored on Google's side between calls.
• explicit: the workspace is uploaded through the Files API once and a Context Cache (caches.create, TTL 1 h by default) is built; repeat questions reference the cache ID and the cached input is billed at Google's cached-input price. The cache is rebuilt whenever a file changes.

The explicit path:

         first call                         repeat calls┌──────────────────────────┐        ┌──────────────────────────┐│  scan workspace           │        │  scan workspace          ││  sha256 each file         │        │  sha256 each file        ││  merge → files_hash       │        │  merge → files_hash      ││                           │        │                          ││  upload changed files →   │        │  hash matches manifest   ││    Files API              │        │  → reuse cached context  ││                           │        │                          ││  caches.create(model,     │        │  generateContent(         ││    contents, ttl=1h)      │        │    cachedContent: ID,    ││    → cache_id             │        │    contents: prompt      ││                           │        │  )                       ││                           │        │                          ││  generateContent(         │        │  response without the    ││    cachedContent: ID,     │        │  upload and cache build  ││    contents: prompt       │        │                          ││  )                        │        │                          │└──────────────────────────┘        └──────────────────────────┘  full input price (125 s measured)    cached-token price (~14 s measured)

Deep dive: docs/how-caching-works.md.

Configuration

Every env var, auth tier and per-call override is listed in docs/configuration.md.

Migrating from gemini-mcp-tool

One-line change in ~/.claude.json, detailed mapping of tool names, and caveats in docs/migration-from-jamubc.md.

Security

• API key stored in ~/.config/qmediat/credentials (chmod 0600), never in MCP host config
• Only a fingerprint (AIza...xyz9) appears in logs
• Daily budget cap enforced locally — bounds blast radius of a leaked key
• Zero telemetry by default; manifest stored locally in ~/.qmediat/
• code tool's codeExecution runs in Google's sandbox, not on your machine

Full threat model + incident response: docs/security.md.

Cost model

Measured 2026-04-22 with explicit cachingMode on vitejs/vite@main's packages/vite/ (~670 k tokens, 451 files, Gemini 3.1 Pro, thinkingLevel: LOW): $0.60 per cached query vs $2.35 per inline query — ~75 % cheaper on cache hit, cold call ~125 s, warm call ~14 s. At 20 queries/day on this workspace that is $35/day per developer ($12 cached vs $47 inline). The implicit default has no guaranteed discount: a repeat query costs at most the inline price. The cost estimator assumes cached input at 25 % of the input rate when a model's price sheet lists no cached rate — check Google's current cached-input price for your model. Actual numbers scale with workspace tokens × queries/day × thinking budget.

Per-tool cost breakdown, free-tier guidance, and all the knobs: docs/cost-model.md.

Architecture

┌──────────────┐   stdio   ┌────────────────────────────────────┐   HTTPS   ┌─────────────┐│  Claude Code │◄─────────►│  @qmediat.io/gemini-code-context-… │◄─────────►│  Gemini API │└──────────────┘           └────────────────────────────────────┘           └─────────────┘                                        │                            ┌───────────┼───────────┬──────────────────┐                            ▼           ▼           ▼                  ▼                     ┌───────────┐ ┌─────────┐ ┌──────────┐     ┌──────────────┐                     │ Workspace │ │  Cache  │ │ Manifest │     │ TTL Watcher  │                     │  Indexer  │ │ Manager │ │ (SQLite) │     │ (background) │                     └───────────┘ └─────────┘ └──────────┘     └──────────────┘

More: docs/architecture.md.

Maintenance & support

This project is built and maintained by Quantum Media Technologies sp. z o.o. — a registered Polish technology company (qmediat.io) — that uses gemini-code-context-mcp in its own Claude Code sessions. The practical consequences for users:

• Bugs that affect real coding sessions get fixed first. Examples: v1.5.1 retry on transient Node fetch failed (caught during a real /coderev run on a large repo), v1.7.0 streaming heartbeat (silent 60-180 s pauses on HIGH thinking were friction for our own team), v1.7.2 fake-timer race in CI (broke the release pipeline — diagnosed via 3-tool model consult, fixed and shipped same day).
• Long-term roadmap, not a weekend project. Commercial backing means the project sits on qmediat.io's product roadmap with allocated engineering time. We are not going to disappear. The full release history, with dates, is in CHANGELOG.md.
• Issues and PRs welcome. File at github.com/qmediat/gemini-code-context-mcp/issues — we aim to answer within 48 hours. For commercial inquiries (custom integrations, support contracts, on-prem deployments): [email protected].
• If this saves you time, please ⭐ star the repo. It is the simplest signal you can send that the work is worth continuing, and it directly helps us justify continued investment.

Contributing

See CONTRIBUTING.md. Short version: TypeScript strict, npm run lint && npm run typecheck && npm test, add a CHANGELOG entry, open a PR.

Trademarks and affiliation

Gemini is a trademark of Google. This is an independent, community-maintained integration published by Quantum Media Technologies sp. z o.o.; it is not affiliated with, sponsored by or endorsed by Google. Use of the Gemini API or CLI through this server is subject to Google's own terms and to your own API key or account.

License

MIT © Quantum Media Technologies sp. z o.o. — see LICENSE.

Part of qmediat's open-source portfolio.

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