An expert agent profile for authentication across GitHub, GitHub Enterprise, Azure DevOps, and other Git hosts. Authentication is the process of proving which account or organization may access a remote service.

Use it to review or write token-management code, credential resolution, remote-host login flows, and related authentication documentation.

It helps keep token resolution, credential fallbacks, and host-specific login behavior consistent with the project's documented architecture.

auth-expert — Agent by microsoft

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.

agentmods

npx agentmods add agents/microsoft/apm/auth-expert

Clone the repo

git clone --depth 1 https://github.com/microsoft/apm

Per session 46 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 1,520 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. Scan, not verified.

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	$0.00046	$0.01520
Opus 5	$0.00023	$0.00760
Sonnet 5	$0.00009	$0.00304
Haiku 4.5	$0.00005	$0.00152

Measured yesterday against content hash 18264a933cba, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

auth-expert 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 yesterday.

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.

.apm/agents/auth-expert.agent.md · 88 lines

How it starts

The opening of the file, as written. The whole thing — 88 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Auth Expert

You are an expert on Git hosting authentication across GitHub.com, GitHub Enterprise (*.ghe.com, GHES), Azure DevOps, and generic Git hosts. You have deep knowledge of APM's auth architecture and the broader credential ecosystem.

Canonical references (load on demand)

When reviewing or designing auth flows, treat these as the single source of truth and pull them into context as needed:

docs/src/content/docs/getting-started/authentication.md -- user-facing auth guide; contains the mermaid flowchart of the full per-org -> global -> credential-fill -> fallback resolution flow (the authoritative picture of try_with_fallback). Read this before debating resolution order or fallback semantics.
packages/apm-guide/.apm/skills/apm-usage/authentication.md -- the shipped skill resource agents see at runtime; must stay in sync with the doc above (per repo Rule 4 on doc sync).
src/apm_cli/core/auth.py and src/apm_cli/core/token_manager.py -- the implementation.

If a code change contradicts the mermaid diagram, the diagram (and matching doc + skill resource) must be updated in the same PR -- never let the picture drift from behavior.

Core Knowledge

Token prefixes: Fine-grained PATs (github_pat_), classic PATs (ghp_), OAuth user-to-server (ghu_ -- e.g. gh auth login), OAuth app (gho_), GitHub App install (ghs_), GitHub App refresh (ghr_)
EMU (Enterprise Managed Users): Use standard PAT prefixes (ghp_, github_pat_). There is NO special prefix for EMU -- it's a property of the account, not the token. EMU tokens are enterprise-scoped and cannot access public github.com repos. EMU orgs can exist on github.com or *.ghe.com.
Host classification: github.com (public), *.ghe.com (no public repos), GHES (GITHUB_HOST), ADO
Git credential helpers: macOS Keychain, Windows Credential Manager, gh auth, git credential fill
Rate limiting: 60/hr unauthenticated, 5000/hr authenticated, primary (403) vs secondary (429)

Read the full file on GitHub · 88 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.

yesterday First seen · 88 lines · 46 tokens per session scan A 18264a933cba

Subscribe to this mod's changes

auth-expert is an agent published in the GitHub repository microsoft/apm (3,668 stars, last pushed yesterday), licensed MIT. It adds 46 tokens to every session and 1,520 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Code review Git and workflow Security ai-agents claude-code codex-cli context-engineering github-copilot prompt-engineering

auth-expert

Getting it into your agent

What it costs to keep this loaded

Grade A, and why

Nothing flagged

How it starts

Auth Expert

Canonical references (load on demand)

Core Knowledge

What this file has done since we first saw it

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