How to use the Design Drift Report agent skill (egm-drift-report)

What is an agent skill and what does this one do?

An agent skill is a folder containing instructions (a SKILL.md file) that an AI agent loads when a request matches the skill. This skill is licensed under Apache-2.0.

When you ask, the agent reads every design document or README in a folder, finds the code those documents describe, and checks whether the code has drifted away from the written spec. It looks for four kinds of difference: missing features, missing fields, hardcoded values where logic was planned, and different libraries or patterns than proposed.

The output is a dated markdown report named {YYYY-MM-DD}_DRIFT_REPORT.md. It lists only the differences for each document, or says 'No drift detected' when the code matches.

Install the egm-drift-report skill

Download the skill ZIP from this page and unzip it. You can install it in one of two ways.

For Claude Code, put the unzipped skill folder in ~/.claude/skills/ to make it available to all your projects, or in a project's .claude/skills/ folder to make it available only to that project.

For the Claude apps, upload the skill under Settings → Capabilities → Skills.

• Personal install: ~/.claude/skills/
• Project install: .claude/skills/ inside your project
• Claude apps: Settings → Capabilities → Skills (upload)

Prepare your design documents and source tree

The skill needs two things the agent can reach: a directory of design documents or READMEs, and the source code tree they describe. The agent must be able to read files and search the source with grep.

Where a design doc does not name the file, class or function it describes, the skill asks you to add those links to the document so future checks are cheaper.

• Design docs or READMEs in one directory the agent can read
• Source code the agent can read and search
• Explicit file, class, function or endpoint names in docs make matching more reliable

Trigger the skill with a natural request

The skill is triggered when you ask the agent to detect drift or check consistency across design documents or READMEs in a directory. Name the directory so the agent knows what to check.

If you do not give a directory, the skill asks you to specify one before it starts.

• Detect drift across all the design docs in docs/designs.
• Check consistency between the READMEs in this repo and the code.
• Run a drift check on the design documents before the release.

Read and act on the drift report

The agent writes one section per design document with a heading named after the document. Each section is a bulleted list of specific divergences, or the line 'No drift detected'.

Because the agent's judgement can miss or invent differences, treat each bullet as a lead to verify, not as a confirmed bug. Check the cited code yourself before changing anything.

• Each section heading is the design document name
• Only differences are listed; matching parts are not described
• Verify every item against the source before acting

Safety notes: scripts and network

This skill does not run scripts and does not use the network, according to its listing. It works through the agent's file read and write tools and search (grep) access to the source tree.

The skill writes its report file to your project, so the agent needs write access to where the report is saved.

• Runs scripts: no
• Uses network: no
• Requires file read and write tools plus grep access

Tips for better drift reports

The skill processes files one at a time so tool output does not overflow. Large document sets will take longer, and the agent may need you to narrow the directory.

The more specific your design docs are about names and behaviour, the more useful the report is. Vague docs give vague results.

• Keep design docs and READMEs in one directory per check
• Name the exact classes, fields and files the doc refers to
• Run the check before releases and review the report in the same pass