docs: document Skill provenance attributes for users who want to track skill origins programmatically

The SDK docs were missing three attributes on the Skill class (handle, source,
revision) and didn't explain the metadata dict contents. Also adds EDITOR/VISUAL
env var note to configuration page for users who hit errors with agr config edit.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: 2 people

docs/docs/configuration.md

@@ -239,7 +239,7 @@ All config operations use the `agr config` command:
 ```bash
 agr config show               # View formatted config
 agr config path               # Print agr.toml path
-agr config edit               # Open in $EDITOR
+agr config edit               # Open in $EDITOR or $VISUAL
 agr config get <key>           # Read a value
 agr config set <key> <values>  # Write a value
 agr config add <key> <values>  # Append to a list
@@ -249,4 +249,11 @@ agr config unset <key>         # Clear to default
 
 Add `-g` to any command to operate on the global config (`~/.agr/agr.toml`).
 
+!!! note "`agr config edit` requires an editor"
+    `agr config edit` opens `agr.toml` in your `$EDITOR` (or `$VISUAL`).
+    If neither environment variable is set, you'll get an error. Set one:
+    ```bash
+    export EDITOR="vim"              # or nano, code --wait, etc.
+    ```
+
 See the [CLI Reference](reference.md) for full details.

docs/docs/sdk.md

@@ -34,7 +34,9 @@ print(skill.prompt)
 
 ### From GitHub
 
-`Skill.from_git()` downloads a skill from GitHub and caches it locally. Subsequent calls use the cache unless the remote has new commits.
+`Skill.from_git()` downloads a skill from GitHub and caches it locally. On
+subsequent calls, agr checks the remote HEAD commit — if the cached revision
+matches, it returns the cached copy without re-downloading.
 
 ```python
 from agr import Skill
@@ -45,7 +47,7 @@ skill = Skill.from_git("kasperjunge/commit")
 # Explicit repo
 skill = Skill.from_git("anthropics/skills/code-review")
 
-# Force re-download (skip cache)
+# Force re-download even if cached (useful after upstream changes)
 skill = Skill.from_git("kasperjunge/commit", force_download=True)
 ```
 
@@ -62,13 +64,53 @@ skill = Skill.from_local("/absolute/path/to/skill")
 
 | Property | Type | Description |
 |----------|------|-------------|
-| `name` | `str` | Skill name |
+| `name` | `str` | Skill name (directory name) |
 | `path` | `Path` | Path to skill directory (cached or local) |
-| `prompt` | `str` | Contents of `SKILL.md` (lazy-loaded) |
-| `files` | `list[str]` | Relative file paths in the skill directory (lazy-loaded) |
-| `metadata` | `dict` | Skill metadata (name, path, source, revision, handle, is_local) |
+| `handle` | `ParsedHandle \| None` | Parsed handle with owner, repo, and name components |
+| `source` | `str \| None` | Source name the skill was fetched from (e.g., `"github"`) |
+| `revision` | `str \| None` | Git commit hash (first 12 chars) of the fetched revision |
+| `prompt` | `str` | Contents of `SKILL.md` (lazy-loaded on first access) |
+| `files` | `list[str]` | Relative file paths in the skill directory (lazy-loaded on first access) |
+| `metadata` | `dict` | Combined metadata dict (see below) |
 | `content_hash` | `str \| None` | Content hash from `.agr.json`, if present |
 
+The `handle`, `source`, and `revision` attributes are set by `from_git()`. For
+locally loaded skills, `source` and `revision` are `None`.
+
+### Provenance: handle, source, revision
+
+When you load a skill from GitHub, agr records where it came from:
+
+```python
+skill = Skill.from_git("anthropics/skills/code-review")
+
+# Which repo was it fetched from?
+print(skill.source)    # "github"
+print(skill.revision)  # "a1b2c3d4e5f6" (short commit hash)
+
+# Access handle components
+print(skill.handle.username)  # "anthropics"
+print(skill.handle.repo)      # "skills"
+print(skill.handle.name)      # "code-review"
+```
+
+### The metadata dict
+
+The `metadata` property returns a dict combining all provenance info:
+
+```python
+skill = Skill.from_git("anthropics/skills/code-review")
+print(skill.metadata)
+# {
+#     "name": "code-review",
+#     "path": "/Users/you/.cache/agr/skills/anthropics/skills/code-review/a1b2c3d4e5f6",
+#     "source": "github",
+#     "revision": "a1b2c3d4e5f6",
+#     "handle": "anthropics/skills/code-review",
+#     "is_local": False,
+# }
+```
+
 ### Reading Files
 
 ```python