/gsd:progress and file write operations trigger recurring 500 Internal Server Error from Anthropic API

Summary

/gsd:progress skill triggers recurring 500 Internal Server Error from Anthropic API when reading planning files

Environment

• Product/Service: Claude Code CLI
• Version: v2.1.56
• Model: claude-sonnet-4-6 (Claude Max plan)
• OS: Windows 11 Pro 10.0.26200
• Shell: bash

Reproduction Steps

1. Open a project with a .planning/ directory (created by /gsd:new-project)
2. Run /gsd:progress
3. Observe the skill executes a bash check (test -d .planning)
4. Observe the skill attempts to read 4 files from .planning/
5. API call fails with 500

Expected Behavior

/gsd:progress reads project state files and returns a progress summary

Actual Behavior

After the bash step succeeds, the subsequent multi-file read triggers a 500 Internal Server Error. The skill aborts with no useful recovery path.

Error Details

API Error: 500 {"type":"error","error":{"type":"api_error","message":"Internal server error"},"request_id":"req_011CYV9fZ5ygPe7cZHEkRdg8"}

Planning Directory at Time of Error

.planning/
├── codebase/
├── milestones/
├── phases/
├── research/
├── config.json      (239 bytes)
├── MILESTONES.md    (5,027 bytes)
├── PROJECT.md       (10,978 bytes)
├── REQUIREMENTS.md  (8,602 bytes)
├── ROADMAP.md       (9,630 bytes)
└── STATE.md         (6,800 bytes)
Total: ~4.5MB (includes subdirs)

Impact

High — Recurring issue (not first occurrence). Core GSD workflow command completely broken on each occurrence, blocking project progress visibility. No workaround within the skill itself.

Additional Context

• This is a recurring issue, not an isolated incident
• The bash step (test -d .planning) succeeds before the failure, confirming the environment is healthy
• Total text file content is ~41KB — not an obvious context size issue
• Request ID for Anthropic engineering: req_011CYV9fZ5ygPe7cZHEkRdg8