docs: document full ULID display in plan tree, add CHANGELOG entry for PR #6571

- docs/reference/plan_cli.md: add Full ULID Display section to agents plan tree
  documenting the change from truncated 8-char IDs to full 26-char ULIDs (PR #6571),
  including the new Decision IDs for correction section and updated examples showing
  direct use of tree output IDs in follow-up commands
- CHANGELOG.md: add Fixed entry for agents plan tree full ULID display (PR #6571)

ISSUES CLOSED: #7674

CHANGELOG.md

@@ -142,6 +142,12 @@ The format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
   that apply is blocked unless at least one validation was actually executed. Also added
   `required_total` property for completeness. Updated `consolidated_validation.feature` scenarios
   to reflect the corrected blocking behavior for empty summaries and no-attachment runs.
+- **`agents plan tree` Full ULID Display** (#6571): The `plan tree` command now
+  displays full 26-character ULIDs for all decision IDs instead of truncated
+  8-character prefixes. Decision IDs shown in the tree output can now be used
+  directly in follow-up commands (`plan explain`, `plan correct`) without
+  looking up the full ID. A new "Decision IDs (for correction)" section lists
+  all decision ULIDs with human-readable labels.
 
 - **Robot Framework TDD Listener Guards** (#5436): Added three guard conditions to the
   `tdd_expected_fail_listener` `end_test()` function to prevent blindly inverting ALL test

docs/reference/plan_cli.md

@@ -251,16 +251,16 @@ Alternatives considered are always included in the output.
 
 ```bash
 # Default rich output
-agents plan explain 01HXYZ1234567890ABCDEFGH
+agents plan explain 01HXYZ1234567890ABCDEFXYZX
 
 # JSON with full context
-agents plan explain 01HXYZ1234567890ABCDEFGH --format json --show-context
+agents plan explain 01HXYZ1234567890ABCDEFXYZX --format json --show-context
 
 # Show reasoning
-agents plan explain 01HXYZ1234567890ABCDEFGH --show-reasoning
+agents plan explain 01HXYZ1234567890ABCDEFXYZX --show-reasoning
 
 # YAML output with all details
-agents plan explain 01HXYZ1234567890ABCDEFGH --format yaml \
+agents plan explain 01HXYZ1234567890ABCDEFXYZX --format yaml \
   --show-context --show-reasoning
 ```
 
@@ -282,21 +282,46 @@ agents plan tree <PLAN_ID> [OPTIONS]
 | `--show-superseded`    | Include superseded decisions in the tree          |
 | `--depth`              | Maximum tree depth (0 = unlimited, default: 0)    |
 
+### Full ULID Display
+
+As of v3.2.0 (PR #6571), `agents plan tree` displays **full 26-character ULIDs**
+for all decision IDs instead of truncated 8-character prefixes.  This means
+every ID shown in the tree output can be used directly in follow-up commands
+such as `agents plan explain` and `agents plan correct` without needing to
+look up the full ID elsewhere.
+
+The output includes a **"Decision IDs (for correction)"** section that lists
+all decision ULIDs with human-readable labels derived from the decision type,
+making it easy to identify which ID to pass to correction commands.
+
+```
+Decision IDs (for correction)
+  01HXYZ1234567890ABCDEFXYZX  strategize: initial strategy
+  01HXYZ1234567890ABCDEFXYZY  execute: write src/foo.py
+  01HXYZ1234567890ABCDEFXYZZ  execute: write tests/test_foo.py
+```
+
 ### Examples
 
 ```bash
-# Default rich tree view
-agents plan tree 01HXYZ1234567890ABCDEFGH
+# Default rich tree view (full ULIDs displayed)
+agents plan tree 01HXYZ1234567890ABCDEFXYZW
 
 # Table format
-agents plan tree 01HXYZ1234567890ABCDEFGH --format table
+agents plan tree 01HXYZ1234567890ABCDEFXYZW --format table
 
 # Include superseded decisions
-agents plan tree 01HXYZ1234567890ABCDEFGH --show-superseded
+agents plan tree 01HXYZ1234567890ABCDEFXYZW --show-superseded
 
 # Limit depth to 2 levels
-agents plan tree 01HXYZ1234567890ABCDEFGH --depth 2
+agents plan tree 01HXYZ1234567890ABCDEFXYZW --depth 2
 
 # JSON output for scripting
-agents plan tree 01HXYZ1234567890ABCDEFGH --format json
+agents plan tree 01HXYZ1234567890ABCDEFXYZW --format json
+
+# Use a decision ID from tree output directly in explain
+agents plan explain 01HXYZ1234567890ABCDEFXYZY
+
+# Correct a decision using a tree ULID directly
+agents plan correct 01HXYZ1234567890ABCDEFXYZZ --mode revert
 ```