Add Definitive Flash plugin (swaps + limit/TWAP/trigger orders, 7 chains)

[sp6pe]

Description

Adds a Base MCP plugin for Definitive Flash (https://flash.definitive.fi/docs) — a trading API routing across 200+ liquidity sources with market, limit, TWAP, stop/stop-loss/take-profit, and bracket orders, plus cross-chain settlement.

Integration shape (http-api, closest precedent: o1.exchange):

• POST /quote returns pricing plus funding payloads (wrap tx, ERC-20 approve calldata) and EIP-712 typed data
• Funding transactions are submitted as unsigned {to, value, data} via send_calls
• Order (and Permit2) payloads are signed via sign (eth_signTypedData_v4); cancel/update use personal_sign over canonical messages
• The signed order is POSTed back to /order; Flash handles gas, simulation, MEV protection, and onchain landing (execution is gasless for the user)

The diff adds skills/base-mcp/plugins/flash.md and appends the net-new cross-chain tag to the vocabulary list in plugin-spec.md, per Contribution Scope.

Allowlist request: please add flash.definitive.fi to the web_request allowlist so chat-only surfaces (Claude.ai / ChatGPT) can reach the POST endpoints. Until then the plugin is fully functional on harness surfaces (Claude Code, Cursor, Codex), and ## Surface Routing stops cleanly on chat-only surfaces.

Verification done while authoring (read-only, against the live API with the public dev key):

• GET /search, GET /balances/{address}, GET /orders — response shapes match the doc
• POST /quote with and without funderAddress — confirmed approveTx/permitTypedData/orderTypedData payloads, and the documented domain.chainId-as-string quirk
• Signing/submit semantics cross-checked against Definitive's own open-source client (@definitive-fi/flash-mcp) and the OpenAPI spec (https://flash.definitive.fi/v1/openapi.json)

Type of change

• Base MCP plugin submission
• Update to an existing skill/plugin
• New skill
• Documentation
• Other (please describe):

Affected skill(s)

base-mcp

Plugin checklist

• Plugin spec/manifest is accurate and tested
• (If Applicable) API endpoints and/or external MCP/CLI tested and functional
• Follows Contribution Scope

Base MCP Plugin Submission Agreement (when applicable)

By checking the box below, I agree and represent on behalf of the protocol/entity it references that:

• I am authorized to submit this plugin on behalf of the protocol/entity it references;

• the plugin does not infringe or misappropriate any third party's rights;

• the plugin and the underlying protocol comply with all applicable laws, and my API enforces the same geofencing and eligibility restrictions as my own user-facing app;

• the plugin is in full compliance with our protocol's/entity's then-current terms and conditions, and if not, submission and use thereafter is considered a formal written exemption to such terms and conditions;

• the plugin accurately describes its behavior and contains no hidden, deceptive, or malicious instructions, and my API will not return malicious or unexpected calldata;

• the protocol/entity is solely responsible for the plugin and is submitting a plugin is subject to the Base Account and Base App Terms of Service as using a "Service"; and

• Base may modify, decline to list, or remove the plugin at any time, for any reason.

• I have read and agree to the Base MCP Plugin Submission Agreement above.

Related issues

N/A — submitted by Definitive (the protocol team behind Flash).

[cb-heimdall]

🟡 Heimdall Review Status

Requirement	Status	More Info
Reviews	🟡 0/1	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 2 if repo is sensitive 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 0 Sum 1