Source Library

Every system REACH can reach into. Claude chooses the right library for each source — you declare the source name, Claude handles the connection.

The rule for browser sources: if curl would return what you need, REACH uses HtmlAgilityPack (fast, no browser process). If the page requires JavaScript or interaction, REACH uses Playwright (full headless Chromium).

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Outlook

Talks directly to your running Outlook instance via COM Interop. No API keys, no Graph auth, no tokens. Works because Outlook is already open.

Source	What it reaches
outlook.inbox	Inbox — filter, count, group by sender/subject/date
outlook.sent	Sent items — communication cadence from your side
outlook.calendar	Calendar entries — meetings, appointments, events
outlook.folder	Any named folder — Deleted Items, custom folders
outlook.draft	Compose an email (does not send until instructed)
outlook.send	Send the composed draft (always preceded by a prompt gate)
outlook.meeting	Compose a meeting invite

Performance: 3-8s cold, 1-2s warm.

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Git

Reads git history. Runs in the current directory or a specified path. No GitHub API — direct git log.

Source	What it reaches
git.commits	Commit history — cadence, after-hours %, velocity
git.log	Raw log with custom shape — author, date, message

After-hours analysis — when analyze after-hours is specified, Claude splits commits by time of day and calculates the percentage outside core hours (9am–6pm). The benchmark (benchmark 15%) turns the number into a verdict.

After-hours %	RPM state	What it signals
0–15%	🟢 Green	Sustainable — occasional late push, not a pattern
15–25%	🟡 Yellow	Watch — creeping into personal time regularly
25–30%	🔴 Red	Running hot — recovery needed
30%+	🔴🔴 All red	Structural overflow — open valley week essential

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Screen

Captures exactly what's visible. Returns an image path — Claude reads it inline and reasons about what it sees.

Source	What it reaches
screen	Full screen capture
screen.window	Specific named window
screen.region	Defined pixel region

Performance: 3-5s cold, under 1s warm. Fastest reach available.

When to use: UI review, deployment state, errors on screen, anything that words don't capture efficiently. Claude reaches for this itself when it determines it needs to see something.

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Browser

Source	When to use	Library
browser.page	Page requires JavaScript, SPA, dynamic content	Playwright — headless Chromium
browser.auth	Login flow before reaching target page	Playwright
http.get	Static page or REST endpoint	HttpClient built-in
http.post	Post to a REST endpoint	HttpClient built-in

Performance: Playwright — 10-20s cold, 6-10s warm. HtmlAgilityPack / HttpClient — near-instant.

Playwright capabilities:

• Navigate to any URL, wait for specific CSS selectors
• Extract text, tables, links from rendered DOM
• Screenshot full page or specific element
• Fill forms, click buttons, navigate through auth flows
• Persist session cookies across steps

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Database

SQL Server queries across named environments. No hardcoded connection strings — Claude maps environment names to connections from your CLAUDE.md.

Source	What it reaches
db.query	Run a SQL query, return results in specified format
db.table	Inspect a table — schema, row count, sample data

Environment names — env dev, env staging, env prod — mapped in CLAUDE.md:

var environments = new Dictionary<string, string>
{
    ["dev"]     = "Server=your-dev-server;Database=YourDb;Integrated Security=true;",
    ["staging"] = "Server=your-staging-server;Database=YourDb;Integrated Security=true;",
    ["prod"]    = "Server=your-prod-server;Database=YourDb;Integrated Security=true;"
};

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Files

Source	What it reaches
file.read	Read .txt, .docx, .pdf — extract as plain text
file.merge	Merge multiple files into one
file.watch	Watch a folder for new files, signal on arrival
file.write	Write findings to a file

Document libraries:

• .docx — DocumentFormat.OpenXml (official Microsoft, handles all Word internals)
• .pdf — PdfPig for text extraction; iTextSharp if layout matters

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UI Automation

Interacts with a running application's UI control tree via Windows UIAutomation. Reads the actual control hierarchy — names, types, values. No screenshots needed for structured data.

Source	What it reaches
ui.window	Any running desktop application

reach ui.window "OUTLOOK"
  find      name "Inbox"
  read      items
  output    list

Library: FlaUI — wraps Windows UIAutomation cleanly. Finds controls by name, type, or automation ID. Clicks buttons, reads list items, types into fields.

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Process

Source	What it reaches
process.launch	Launch an application
process.signal	Write a signal file for inter-reach communication

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Timesheet

Posts entries to your organization's timesheet system. Always preceded by a prompt gate — never posts silently.

Source	What it reaches
timesystem.timesheet	Draft timesheet entries from git + calendar analysis
timesystem.post	Post reviewed entries

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CI/CD

Source	What it reaches
ci.pipeline	Watch a CI/CD pipeline URL for status changes
ci.error-log	Read error output from the most recent pipeline run

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How Claude Chooses Libraries

Claude selects the least-friction library for the task. Built-ins first.

Situation	Claude reaches for
File is .docx	DocumentFormat.OpenXml — official, handles all Word internals
File is .pdf	PdfPig for text, iTextSharp if layout matters
Outlook is open	COM Interop — no auth, talks to live instance directly
SQL Server query	Microsoft.Data.SqlClient — modern, works across all environments
UI interaction needed	FlaUI — wraps Windows UIAutomation cleanly
Screen capture	System.Drawing built-in — no package, fastest reach
Page needs JavaScript	Microsoft.Playwright — real headless Chromium
Page is static HTML	HtmlAgilityPack — fast, no browser process
Simple HTTP / REST	HttpClient built-in — no package needed
Structured output	System.Text.Json built-in, or CsvHelper for CSV