feat: load .env in hooks for API keys (GIT-94)

[TonyCasey]

Summary

• Add dotenv dependency to load .env from repository root
• Hooks now automatically pick up ANTHROPIC_API_KEY for LLM enrichment
• No manual export required

Test plan

• Verified LLM enrichment works with .env file
• AI-Source: llm-enrichment shown in commit trailers
• Git notes contain LLM-generated content

Closes GIT-94

🤖 Generated with Claude Code

Summary by CodeRabbit

• New Features
  • Hooks now load environment variables from a repository-root .env file before processing, affecting hook behavior based on repo-level env values.
• Chores
  • Added a runtime dependency to support loading environment variables from .env.

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[coderabbitai]

📝 Walkthrough

Walkthrough

Adds dotenv as a runtime dependency and changes the hook command to resolve the repository root, load a .env from that root, then load hook configuration and proceed with hook processing.

Changes

Cohort / File(s)	Summary
Package Dependencies package.json	Added dotenv (^17.3.1) to dependencies.
Hook Command Initialization src/commands/hook.ts	Added path and child_process imports, findGitRoot helper; compute repo root, load .env from repo root via dotenv.config() before loading hook config and continuing hook processing.

Sequence Diagram(s)

sequenceDiagram
  autonumber
  participant Input
  participant HookCmd as Hook Command
  participant Git as Git CLI
  participant Env as .env loader
  participant Config as Hook Config
  participant Hook as Hook Executor

  Input->>HookCmd: invoke hook command (with cwd?)
  HookCmd->>Git: git rev-parse --show-toplevel
  Git-->>HookCmd: repo root (or fallback cwd)
  HookCmd->>Env: load .env from repo root
  Env-->>HookCmd: environment variables loaded
  HookCmd->>Config: loadHookConfig(repoRoot)
  Config-->>HookCmd: hook configuration
  HookCmd->>Hook: isEventEnabled & process hooks
  Hook-->>HookCmd: hook results
  HookCmd-->>Input: exit / output

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Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related PRs

• feat: prepare-commit-msg hook for passive AI-Agent trailer injection (GIT-70) #41: Changes related to prepare-commit-msg hook behavior and environment availability (both affect hook initialization and rely on loading .env).

🚥 Pre-merge checks | ✅ 3 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 66.67% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'feat: load .env in hooks for API keys (GIT-94)' directly and clearly summarizes the main change: loading environment variables from a .env file in git hooks to support API keys.
Merge Conflict Detection	✅ Passed	✅ No merge conflicts detected when merging into main

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch git-88

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[Copilot]

Pull request overview

Adds automatic .env loading to the git-mem hook command so hook executions can pick up API keys (notably ANTHROPIC_API_KEY) for LLM enrichment without requiring users to manually export environment variables.

Changes:

• Load .env (from cwd) at the start of hookCommand execution.
• Add dotenv as a runtime dependency.
• Update package-lock.json accordingly.

Reviewed changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated 2 comments.

File	Description
src/commands/hook.ts	Loads .env prior to reading hook config / dispatching events.
package.json	Adds dotenv dependency.
package-lock.json	Locks dotenv dependency resolution.

---

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[Copilot]

New behavior: hooks now load .env and mutate process.env before reading config/dispatching. There are existing unit/integration tests for hook behavior, but none assert that .env loading works (or that it doesn’t affect unrelated env vars). Adding an integration test that writes a .env in the temp repo and verifies the hook picks up a value from it would prevent regressions.

[TonyCasey]

Good point on test coverage. The existing hook integration tests cover the commit-msg flow but don't specifically test .env loading. Will defer adding that test to a follow-up since we've manually verified the end-to-end flow works.

[Copilot]

The comment says this loads .env from the repository root, but the path is derived from cwd (stdin-provided working directory). If cwd is a subdirectory or not the repo top-level, this will silently miss the intended .env (and .git-mem.json), leading to hooks not picking up API keys. Consider resolving the git top-level (e.g., via git rev-parse --show-toplevel using cwd as the working dir) and loading .env from there, or adjust the comment/behavior accordingly.

[TonyCasey]

Fixed in 6abf8ea - now uses git rev-parse --show-toplevel to find the actual repo root, with graceful fallback to cwd if git fails.

[coderabbitai]

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

src/commands/hook.ts (1)

142-153: 🧹 Nitpick | 🔵 Trivial

Consider loading .env only when event is enabled.

Currently, .env is loaded before checking if the event is enabled (line 150). This means environment loading occurs even for disabled hooks. While the overhead is minimal, you could optimize by moving the isEventEnabled check earlier:

     const cwd = input.cwd ?? process.cwd();
     const repoRoot = findGitRoot(cwd);
+    const config = loadHookConfig(repoRoot);
+
+    if (!isEventEnabled(config.hooks, eventName)) {
+      clearTimeout(timer);
+      return;
+    }

     // Load .env from repository root for API keys (e.g., ANTHROPIC_API_KEY)
     loadEnv({ path: join(repoRoot, '.env'), quiet: true });
-
-    const config = loadHookConfig(repoRoot);
-
-    if (!isEventEnabled(config.hooks, eventName)) {
-      clearTimeout(timer);
-      return;
-    }

This avoids filesystem access for the .env file when the hook is disabled.