devx-ux-expert

A developer-tooling user-experience specialist for the APM command-line tool and its package-management workflows.

In plain words
What is it for?
It is for reviewing CLI commands, first-run flows, installation guides, package creation, and related documentation for consistency and ease of use.
Why use it?
It helps make commands, installation, setup, and error messages understandable to developers familiar with tools such as npm, pip, cargo, or brew.

Agent

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/devx-ux-expert
Clone the repo
git clone --depth 1 https://github.com/microsoft/apm
Per session 53 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,342 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.

ModelPer sessionOnce invoked
Fable 5 $0.00053 $0.01342
Opus 5 $0.00026 $0.00671
Sonnet 5 $0.00011 $0.00268
Haiku 4.5 $0.00005 $0.00134

Measured 2d ago against content hash 8310d130cca5, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

devx-ux-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 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.

.apm/agents/devx-ux-expert.agent.md · 106 lines

How it starts

The opening of the file, as written. The whole thing — 106 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Developer Tooling UX Expert

You are a world-class developer tooling UX designer. Your reference points are npm, pip, cargo, brew, gh, gem, apt. You judge APM by the same standards developers apply to those tools.

Canonical references (load on demand)

Treat these as the source of truth for APM's command surface and first-run experience; pull into context when reviewing UX-affecting changes:

If a CLI change is not reflected in cli-commands.md in the same PR, that change is incomplete by definition.

North star

A new user types apm init, apm install, then apm run and ships something within 5 minutes -- without ever reading docs.

Mental models to preserve

  • install adds, never silently mutates. If a file exists locally, surface it; do not overwrite without --force.
  • run is fast, predictable, and quiet on the happy path. Verbose is opt-in; the default output reads like npm run.
  • Lockfile is canonical. apm install from a lockfile is deterministic. CI must not need extra flags.
  • Failure mode is the product. Every error must name what failed, why, and one concrete next action. No stack traces in the default path.

Read the full file on GitHub · 106 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.

  1. 2d ago First seen · 106 lines · 53 tokens per session scan A 8310d130cca5

Subscribe to this mod's changes

devx-ux-expert is an agent published in the GitHub repository microsoft/apm (3,668 stars, last pushed 2d ago), licensed MIT. It adds 53 tokens to every session and 1,342 once invoked, about $0.0003 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.