Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add cyanheads/mailchimp-mcp-server --skill api-workersgit clone --depth 1 https://github.com/cyanheads/mailchimp-mcp-serverWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/cyanheads/mailchimp-mcp-server/api-workers)<a href="https://agentmods.dev/skills/cyanheads/mailchimp-mcp-server/api-workers"><img src="https://agentmods.dev/badge/skills/cyanheads/mailchimp-mcp-server/api-workers/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/cyanheads/mailchimp-mcp-server/api-workers"><img src="https://agentmods.dev/badge/skills/cyanheads/mailchimp-mcp-server/api-workers.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00051 | $0.03756 |
| Opus 5.5 | $0.00020 | $0.01502 |
| Sonnet 5.5 | $0.00010 | $0.00751 |
| Haiku 4.5 | $0.00005 | $0.00376 |
Grade A, and why
api-workers scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 10d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
await worker.fetch(request, r2Env, ctx); This is a copy
100% identical to api-workers — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 320 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Overview
@cyanheads/mcp-ts-core/worker exports createWorkerHandler — the Workers entry point. It wraps tool/resource/prompt registries into a per-request McpServer factory that integrates with the Cloudflare Workers runtime.
createWorkerHandler(options)
import { createWorkerHandler } from '@cyanheads/mcp-ts-core/worker';
import { echoTool } from './mcp-server/tools/definitions/echo.tool.js';
import { echoResource } from './mcp-server/resources/definitions/echo.resource.js';
import { echoPrompt } from './mcp-server/prompts/definitions/echo.prompt.js';
import { initMyService } from './services/my-domain/my-service.js';
export default createWorkerHandler({
tools: [echoTool],
resources: [echoResource],
prompts: [echoPrompt],
setup(core) {
initMyService(core.config, core.storage);
},
extraEnvBindings: [['MY_API_KEY', 'MY_API_KEY']],
extraObjectBindings: [['MY_CUSTOM_KV', 'MY_CUSTOM_KV']],
onScheduled: async (controller, env, ctx) => {
// Cloudflare cron trigger handler
},
});
Fresh scaffolds register definitions directly in the entry point as shown above. If your project later adds barrel files for definitions, importing arrays from those barrels is also fine.
Options
| Option | Type | Purpose |
|---|---|---|
tools |
AnyToolDefinition[] |
Tool definitions to register |
resources |
AnyResourceDefinition[] |
Resource definitions to register |
prompts |
PromptDefinition[] |
Prompt definitions to register |
extensions |
Record<string, object> |
SEP-2133 extensions to advertise in server capabilities |
instructions |
string | (env: CloudflareBindings) => string |
Server-level orientation forwarded to the model on every initialize. Resolver form runs inside initializeApp(env) so env-derived text is available (see Workers-specific warnings). Empty string treated as unset. |
setup |
(core: CoreServices) => void | Promise<void> |
Runs after core services are ready, during the first request (lazy init inside the fetch handler) |
extraEnvBindings |
[bindingKey: string, processEnvKey: string][] |
Maps CF string bindings to process.env keys |
extraObjectBindings |
[bindingKey: string, globalKey: string][] |
Maps CF object bindings (KV, R2, D1, AI) to globalThis keys |
onScheduled |
(controller, env, ctx) => Promise<void> |
Cloudflare cron trigger handler |
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 10d ago Changed · +2 lines 95c2a56eac37
- 1mo ago Changed 1690600e0552
- 1mo ago First seen · 318 lines · 51 tokens per session scan A 7979fbfdc182
api-workers is a skill published in the GitHub repository cyanheads/mailchimp-mcp-server (2 stars, last pushed 4d ago), licensed Apache-2.0. It adds 51 tokens to every session and 3,756 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). It is 100% identical to api-workers, differing in 0 lines, and is treated as a copy.
Other skills, from other repositories
api-workers
Cloudflare Workers deployment using createWorkerHandler from @cyanheads/mcp-ts-core/worker. Covers the full handler signature, binding types, CloudflareBindings extensibility, runtime compatibility guards, and wrangler.toml requirements.
incident-response-skill
A skill that uses object-style tool references with purpose descriptions and required flags, plus strict validation.
add-export
Add a new subpath export to the @cyanheads/mcp-ts-core package. Use when creating a new public API surface that consumers import from a dedicated subpath (e.g., @cyanheads/mcp-ts-core/newutil).
prism-startup
Activate on the first user turn of every conversation, including greetings. Load Prism context using the user's configured project and quick, standard, or deep depth, then greet the developer by their configured agent name and show the matching recent-session context.
Verification Planner
Mandates generation of testassertions.json during planning. v7.2.0 enhanced with severity gates (warn/gate/abort), dependency chains, and Claw-as-Validator support.
typescript-lsp
Search TypeScript SYMBOLS (functions, types, classes) - NOT text. Use Glob to find files, Grep for text search, LSP for symbol search. Provides type-aware results that understand imports, exports, and relationships.