What is http-mcp-headers?

Implementation guidance for passing secret values through HTTP headers in GitHub Actions MCP configurations. GitHub Actions is a service for running automated workflows, and MCP is a way for an agent to connect to external tools.

Use it when configuring an HTTP MCP server whose headers contain GitHub Actions secrets, such as credentials for accessing Datadog dashboards, service-level objectives, or metrics.

It prevents API keys and other secret values from being hard-coded while still making them available to an HTTP-connected service. It also keeps the workflow and connection configuration aligned.

http-mcp-headers — Skill for Claude Code and Codex by github/gh-aw

About the project

GitHub Agentic Workflows is a GitHub CLI extension that lets developers define AI-assisted repository automation in Markdown and run it through GitHub Actions. It is intended for tasks requiring interpretation or reasoning, such as issue triage, pull-request review, CI investigation, documentation maintenance, and dependency analysis. The catalogue entries provide skills and agents for working with these workflows.

github/gh-aw · 5,579 stars · on GitHub · gh.io

Install

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.

Any agent

npx skills add github/gh-aw --skill http-mcp-headers

Clone the repo

git clone --depth 1 https://github.com/github/gh-aw

Made for: Claude Code, Codex.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/github/gh-aw/http-mcp-headers/github.svg)](https://agentmods.dev/skills/github/gh-aw/http-mcp-headers)

Your own site

<a href="https://agentmods.dev/skills/github/gh-aw/http-mcp-headers"><img src="https://agentmods.dev/badge/skills/github/gh-aw/http-mcp-headers/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/github/gh-aw/http-mcp-headers"><img src="https://agentmods.dev/badge/skills/github/gh-aw/http-mcp-headers.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 18 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,194 The whole file, excluding the scripts and references it only reads on demand.

Security scan C 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits

NVIDIA SkillSpector pass 7 Sept 2026

How audits are shown

Origin original No closer match found in the catalogue.

Token cost

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	$0.00018	$0.01194
Opus 5.5	$0.00007	$0.00478
Sonnet 5.5	$0.00004	$0.00239
Haiku 4.5	$0.00002	$0.00119

Measured 2mo ago against content hash 537d2fff1660, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade C, and why

http-mcp-headers scanned grade C 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 2mo 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.

Harvests environment variableshighData exfiltration

Enumerating or grepping the environment for keys collects credentials unrelated to what the mod says it does.

1. Extract secrets from headers (e.g., `${{ secrets.DD_API_KEY }}`)

.github/skills/http-mcp-headers/SKILL.md · 152 lines

How it starts

The opening of the file, as written. The whole thing — 152 lines — stays where its author put it; the contents beside it link to each section on GitHub.

HTTP MCP Header Secret Support - Implementation Summary

Use this reference for HTTP MCP header secret support in the copilot engine.

Problem Statement

When HTTP MCP headers include GitHub Actions secrets, mcp-config.json must:

Extract secrets from headers (e.g., ${{ secrets.DD_API_KEY }})
Declare those env variables in the execution step
Configure the MCP config's "env" section to passthrough those variables
Use the passed variables in the headers section

Example Workflow

on:
  workflow_dispatch:
permissions:
  contents: read
engine: copilot
mcp-servers:
  datadog:
    type: http
    url: "https://mcp.datadoghq.com/api/unstable/mcp-server/mcp"
    headers:
      DD_API_KEY: "${{ secrets.DD_API_KEY }}"
      DD_APPLICATION_KEY: "${{ secrets.DD_APPLICATION_KEY }}"
      DD_SITE: "${{ secrets.DD_SITE || 'datadoghq.com' }}"
    allowed:
      - search_datadog_dashboards
      - search_datadog_slos
      - search_datadog_metrics
      - get_datadog_metric

# Datadog Dashboard Search

Search for Datadog dashboards and provide a summary.

Generated Output

1. MCP Config (mcp-config.json)

{
  "mcpServers": {
    "datadog": {
      "type": "http",
      "url": "https://mcp.datadoghq.com/api/unstable/mcp-server/mcp",
      "headers": {
        "DD_API_KEY": "${DD_API_KEY}",
        "DD_APPLICATION_KEY": "${DD_APPLICATION_KEY}",
        "DD_SITE": "${DD_SITE}"
      },
      "tools": [
        "search_datadog_dashboards",
        "search_datadog_slos",
        "search_datadog_metrics",
        "get_datadog_metric"
      ],
      "env": {
        "DD_API_KEY": "\\${DD_API_KEY}",
        "DD_APPLICATION_KEY": "\\${DD_APPLICATION_KEY}",
        "DD_SITE": "\\${DD_SITE}"
      }
    }
  }
}

2. Execution Step Environment Variables

env:
  DD_API_KEY: ${{ secrets.DD_API_KEY }}
  DD_APPLICATION_KEY: ${{ secrets.DD_APPLICATION_KEY }}
  DD_SITE: ${{ secrets.DD_SITE || 'datadoghq.com' }}
  COPILOT_GITHUB_TOKEN: ${{ secrets.COPILOT_GITHUB_TOKEN }}
  # ... other env vars

Read the full file on GitHub · 152 lines

Changes

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.

2mo ago First seen · 152 lines · 18 tokens per session scan C 537d2fff1660

Subscribe to this mod's changes

http-mcp-headers is a skill published in the GitHub repository github/gh-aw (5,579 stars, last pushed yesterday), licensed MIT. It adds 18 tokens to every session and 1,194 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it C with 1 finding (harvests environment variables). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Backend and APIs Claude Code Security actions cai ci codex gh-extension

http-mcp-headers next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
http-mcp-headersgithub/gh-aw	Skill	5.6k	yesterday	MIT	C	18	Claude Code, Codex
argot-suggest-rulesget-tmonier/argot	Skill	52	4d ago	MIT	A	173	Claude Code
remix-expertpersonamanagmentlayer/pcl	Skill	44	11d ago	Apache-2.0	A	70	Claude Code
watch-prjustincampbell/gh-watch	Skill	4	7d ago	MIT	A	48	Claude Code
watch-tagjustincampbell/gh-watch	Skill	4	7d ago	MIT	A	62	Claude Code
watch-branchjustincampbell/gh-watch	Skill	4	7d ago	MIT	A	45	Claude Code
watch-commitjustincampbell/gh-watch	Skill	4	7d ago	MIT	A	48	Claude Code

http-mcp-headers