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 agentmods add rules/zackiles/deno-kit/with-mcpgit clone --depth 1 https://github.com/zackiles/deno-kitWhat 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 | $0.00000 | $0.04665 |
| Opus 5 | $0.00000 | $0.02332 |
| Sonnet 5 | $0.00000 | $0.00933 |
| Haiku 4.5 | $0.00000 | $0.00466 |
Grade A, and why
with-mcp scanned grade A with 0 findings 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 2d 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.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
This is a copy
92% identical to with-mcp — 6 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 — 600 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Context on a Model Context Protocol (MCP) Server
You're working on an MCP server and must use this information to guide your decisons and opinions. MCP servers provide LLMs with tools, resources, and prompts they can access with either stdio or server side events (WebSockets).
MCP Message Types
Protocol: JSON-RPC2.0
Requests → Initiate operations; require a unique ID and method name.
Responses → Reply to requests; must include the same ID as the request.
Notifications → One-way messages; must not include an ID.
MCP Clien/Server Lifecycle
Initialization Phase:
- Client sends
initializerequest with protocol version, capabilities, and implementation info. - Server responds with its protocol version and capabilities.
- Client sends
initializednotification after successful initialization.
Version Negotiation:
- Client proposes protocol version in
initializerequest. - Server responds with supported version.
- If versions are incompatible, client should disconnect.
Capability Negotiation:
- Both client and server declare supported capabilities during initialization.
- Key capabilities:
- Client:
roots: Provides filesystem roots.sampling: Supports LLM sampling requests.
- Server:
prompts: Offers prompt templates.resources: Provides readable resources.tools: Exposes callable tools.logging: Emits structured log messages.
- Client:
Operation Phase:
- After initialization, normal protocol operations commence.
Shutdown Phase:
- Client disconnects to terminate the connection gracefully.
MCP Tools
Purpose
Facilitates LLM interaction with external systems (APIs, databases, computations) via server-exposed tools.
](mdc:https:/spec.modelcontextprotocol.io/specification/2024-11-05/server/tools)
Endpoints
tools/list
- Request: Optional
cursorfor pagination. - Response: List of tools +
nextCursorif more available.
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.
- 2d ago First seen · 600 lines · 0 tokens per session scan A 6bf8a4072fa0
with-mcp is a cursor rule published in the GitHub repository zackiles/deno-kit (3 stars, last pushed 5mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 4,665 tokens. A static security scan graded it A with 0 findings. It is 92% identical to with-mcp, differing in 6 lines, and is treated as a copy.
Other cursor rules, from other repositories
prefer-assertions-over-defensive-checks
Prefer assertions over defensive checks when data is guaranteed to be valid.
as-contract-cast-smell
// ❌ WRONG — bypasses the family ContractSerializer seam const contract = JSON.parse(raw) as Contract; const contract = JSON.parse(raw) as Contract .
no-barrel-files
Avoid barrel files and unnecessary re-exports.
no-family-vocabulary-in-framework
The framework domain (packages/1-framework) carries no family- or target-specific vocabulary — types, fields, hooks, or strategy values. Enforced by the no-family-vocabulary Biome plugin plus lint:framework-vocabulary.
interface-factory-pattern
Interface-based design with factory functions (keep classes private).
explicit-opt-in-over-diagnostics
Prefer requiring explicit opt-in over emitting diagnostics on intentional user paths.