Cambrian API MCP

Model Context Protocol server for the Cambrian API. It exposes the same product surface as the cambrian CLI for agents that need live DeFi, social intelligence, risk, and API documentation tools.

Every call needs a Cambrian API key supplied by the caller. The hosted server and local package both require one; the server never ships or proxies a shared key. Create a key at https://console.cambrian.org/. For x402 pay-per-call access without an API key, use cambrian pay --help; MCP transport still requires a caller-supplied key.

What You Get

• a progressive default profile with one concise tool per public Cambrian API endpoint
• compact and full profiles for clients with different tool-loading behavior
• a composite workflow tool for Solana token snapshots
• cambrian_docs for live endpoint and guide docs from https://docs.cambrian.org/llms.txt
• stdio transport for local MCP clients
• Streamable HTTP transport for hosted and self-hosted deployments

Tool Profiles

| Profile | stdio | HTTP | Tool metadata | | --- | --- | --- | --- | | Progressive (default) | no flag, or --profile progressive | /mcp | Direct endpoint tools with types, required fields, scalar enums, OpenAPI defaults, numeric bounds, and array item types. | | Compact | --profile compact | /mcp/compact | Three tools: cambrian_docs, cambrian_call, and cambrian_solana_token_snapshot. | | Full | --profile full | /mcp/full | Direct endpoint tools with complete request descriptions, defaults, constraints, and response-size controls. |

All profiles use the same progressive documentation flow. cambrian_docs returns the request schema by default. Set detail to response for response fields. The response view also includes the request schema. Set detail to full only for examples and all endpoint prose. The full profile does not preload response documentation for every endpoint.

Progressive omits repeated endpoint descriptions, long patterns, large array enums, and parameter prose. Call cambrian_docs for these details.

Progressive also omits offset, order_asc, and order_desc. These three are the same on every endpoint that has them, and Progressive already strips the per-endpoint sortable-column enum, so repeating them adds about 10 kB to the tool list and tells the agent nothing. The server instructions name them once, and every endpoint still accepts them. limit stays, with its maximum, because it is how an agent bounds a response.

Toolsets

The whole catalog is 141 tools. An agent that only asks about Solana still pays for 99 EVM tools it will never call. Use --toolsets to load only what you need.

| Toolset | Tools | | --- | --- | | solana | cambrian_solana_* and the Solana token snapshot | | evm | cambrian_base_*, cambrian_ethereum_*, and cambrian_arbitrum_* | | deep42 | cambrian_deep42_* | | risk | cambrian_risk_* |

npx -y cambrian-api-mcp --toolsets solana,risk
CAMBRIAN_TOOLSETS=solana npx -y cambrian-api-mcp

Over HTTP, select per request: https://mcp.cambrian.org/mcp?toolsets=solana.

Omit the option, or pass all, to get every tool. cambrian_docs is always present, so a narrowed client can still discover and read about any endpoint.

Progressive tools/list sizes:

| Selection | Tools | Bytes | | --- | --- | --- | | default (all) | 141 | 33,869 | | evm | 99 | 22,471 | | solana | 37 | 10,904 | | deep42 | 6 | 3,663 | | risk | 2 | 2,093 |

How MCP Clients Load Tools

The MCP client receives the complete tools/list result for the selected profile. MCP does not control how much of that result enters the model context.

Claude Code normally loads tool names and server instructions first. It loads complete selected tool definitions after Tool Search. Codex can do the same when its Tool Search feature is available. Other clients can load every tool definition at the start.

The client loads the definition from the selected profile. It does not restore fields that Progressive omitted. Use cambrian_docs to load the complete request schema, response fields, and examples.

Agent Skill

New users and agent runtimes should start here: skills/cambrian-mcp/SKILL.md. It covers Cambrian API key auth, hosted and local client config, tool naming, cambrian_docs lookup, composite tools, response limits, and error handling in one document.

For the CLI instead of MCP, see the cambrian CLI skill.

Recommended Setup Through The CLI

The cambrian CLI prints and tests ready-to-use MCP client config:

npm install -g cambrian
cambrian mcp config --mode hosted
cambrian mcp config --mode local
cambrian mcp install --client claude --mode hosted
cambrian mcp test --mode hosted

Local stdio

Run the published package directly:

export CAMBRIAN_API_KEY=<your-api-key>
npx -y cambrian-api-mcp

Select another profile only when your MCP client needs it:

npx -y cambrian-api-mcp --profile compact
npx -y cambrian-api-mcp --profile full

Narrow the catalog to the toolsets you need:

npx -y cambrian-api-mcp --toolsets solana,risk

Or install it globally:

npm install -g cambrian-api-mcp
export CAMBRIAN_API_KEY=<your-api-key>
cambrian-api-mcp

Hosted Streamable HTTP

Use the CLI to print the current hosted URL and client-specific config:

cambrian mcp config --mode hosted

Direct Claude setup:

claude mcp add --transport http cambrian \
  https://mcp.cambrian.org/mcp \
  --header "Authorization: Bearer YOUR_CAMBRIAN_API_KEY"

Codex config uses TOML:

[mcp_servers.cambrian]
url = "https://mcp.cambrian.org/mcp"
bearer_token_env_var = "CAMBRIAN_API_KEY"

The default URL uses the progressive profile. Use https://mcp.cambrian.org/mcp/compact or https://mcp.cambrian.org/mcp/full for another profile.

HTTP requests must include one of:

Authorization: Bearer <CAMBRIAN_API_KEY>
X-Cambrian-Api-Key: <CAMBRIAN_API_KEY>

Self-Hosted HTTP

npm install
npm run build
node dist/index.js --transport http --host 127.0.0.1 --port 8080

Health endpoint:

curl http://127.0.0.1:8080/health

For hosted deployments, bind to 0.0.0.0:

node dist/index.js --transport http --host 0.0.0.0 --port 8080

Tool Names

Tool names are canonical and prefixed with cambrian_.

Examples:

• cambrian_base_dexes
• cambrian_ethereum_dexes
• cambrian_arbitrum_dexes
• cambrian_solana_price_current
• cambrian_deep42_social_data_alpha_tweet_detection
• cambrian_risk_perp_risk_engine
• cambrian_docs
• cambrian_solana_token_snapshot

Call cambrian_docs without a path to discover the live root index, or use guides/<slug> (for example, guides/x402) for any guide listed there. For an endpoint path, omit detail to get its request schema. Use detail: "response" for response fields and detail: "full" for examples and all endpoint prose.

Endpoint tools come from the same validated runtime registry as the CLI. MCP rechecks that local cache for each tool-list/tool-call request, while OpenAPI network attempts are coalesced and limited to once per source every 15 minutes. If runtime discovery is unavailable, the bundled inventory remains available without changing existing tool names or schemas. That inventory is this package's own snapshot of the live OpenAPI (src/generated/offline-registry.ts, regenerated with npm run registry:generate), not the cambrian package's bundled registry, so the offline catalog does not drift with that package's release cadence.

The API serves one generic /api/v1/evm/* surface whose chain_id parameter lists the chains each endpoint supports. The MCP turns that into one fixed-chain tool per supported chain, so an agent never has to remember a magic number and cannot aim an endpoint at a chain it rejects:

| Chain | Id | Tool prefix | | --- | --- | --- | | Base | 8453 | cambrian_base_* | | Ethereum | 1 | cambrian_ethereum_* | | Arbitrum | 42161 | cambrian_arbitrum_* |

A tool appears for a chain if and only if that endpoint's own chain_id schema allows the chain — from its enum, a fixed minimum/maximum pair, or an exclusive bound. No allowlist and no per-endpoint special case: an endpoint the API widens to enum: [1, 8453, 42161] gains Arbitrum tools on the next metadata load with no MCP change. Base tools fix chain_id to 8453, Ethereum tools to 1, and Arbitrum tools to 42161.

cambrian_docs accepts an optional chain segment in an EVM path, by id or slug: evm/42161/dexes, evm/arbitrum/dexes, and evm/dexes all resolve the same endpoint, with the chain-scoped forms returning that chain's pinned schema.

The chain registry lives in EVM_CHAINS in src/server.ts and is the only place a chain is declared. To add a chain, add one entry there and run npm run registry:generate; see .claude/skills/adding-a-chain/SKILL.md.

Development

npm ci
npm test
npm run build
npm pack --dry-run

The package depends on the published cambrian package for shared metadata and the API client. Publish cambrian first when changing both packages together, then refresh this package lock and deploy the MCP server through CI/CD.

Deployment

Deployments are handled by GitHub Actions and Cloud Run from the private source repository. Do not deploy manually.

The workflow:

1. installs dependencies
2. validates package.json#mcpName matches server.json#name
3. validates package.json#version matches server.json#version
4. builds and tests
5. builds the Docker image
6. deploys to Cloud Run
7. smoke-checks staging directly; production is smoke-tested through the public edge URL after DNS and certificate activation

Registry

The official MCP Registry publishes this server under:

io.github.cambriannetwork/cambrian-api

The manifest uses https://mcp.cambrian.org/mcp, which matches the production edge URL. The public release workflow publishes each new Registry version after npm publication.