What this error means
Context limit reached is a Claude Code failure pattern reported for developers trying to fix claude code slash commands failing with 'context limit reached' false positive on 1m context models when context is far below actual limit. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.
Why this happens
Issue #59143: user on claude-opus-4-7[1m] with ~200k context gets 'Context limit reached' on bare slash commands. Same skill works when prefixed with text. The error message provides no hint about which cap was tripped or the workaround.
Common causes
- On Opus 4.7 1M-token context model, invoking a bare slash command fails with 'Context limit reached' even when context usage is well below 1M (e.g., ~200k). The slash-command loader appears to check against a stale 200k cap instead of the model's actual 1M limit. Workaround: prefix the slash command with any text.
- Issue #59143: user on claude-opus-4-7[1m] with ~200k context gets 'Context limit reached' on bare slash commands. Same skill works when prefixed with text. The error message provides no hint about which cap was tripped or the workaround.
Quick fixes
- Confirm the exact error signature matches
Context limit reached. - Check the Claude Code account, local tool state, and provider configuration involved in the failing workflow.
- Compare the failing environment with a known working setup, then change one configuration value at a time.
Platform/tool-specific checks
- Verify the command, editor, extension, or API client that produced the error.
- Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
- Avoid deleting credentials, local model data, or project settings until the failing scope is clear.
Step-by-step troubleshooting
- Capture the exact error message and the command, editor action, or request that triggered it.
- Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
- Review the source evidence below and compare it with your environment.
- Apply one change at a time and rerun the smallest failing action.
- Keep the working fix documented for the team or deployment environment.
How to prevent it
- Keep provider/tool configuration documented.
- Record non-secret diagnostics such as tool version, provider name, model name, and command path.
- Add a lightweight check before CI or production workflows depend on the tool.