headroom/docs
Abhay Singh 2a8472525d
feat(wrap/claude): make the --1m fallback model configurable via HEADROOM_1M_MODEL (#2983)
## Description

The model `headroom wrap claude --1m` falls back to (when no model is
otherwise selected) was a hardcoded constant `claude-opus-4-8`, with no
env var or config key to override it. So it goes stale with every new
Opus release, and the only workaround is pinning `ANTHROPIC_MODEL`
globally -- which also changes every non-`--1m` session and overrides
Claude Code's own `/model` picker. The knob the user actually wants
("what should `--1m` default to") did not exist (#2937).

## Fix

Add a `HEADROOM_1M_MODEL` env override that `_resolve_1m_model` consults
for its fallback default, and bump the built-in default to
`claude-opus-5` (Opus 5 has shipped):

```python
_1M_MODEL_ENV = "HEADROOM_1M_MODEL"
_DEFAULT_1M_MODEL = "claude-opus-5"

def _resolve_1m_model(current: str | None) -> str:
    fallback = (os.environ.get(_1M_MODEL_ENV) or "").strip() or _DEFAULT_1M_MODEL
    base = (current or "").strip() or fallback
    return base if base.endswith(_CONTEXT_1M_SUFFIX) else f"{base}{_CONTEXT_1M_SUFFIX}"
```

Precedence is unchanged: an explicit `ANTHROPIC_MODEL` (or a
pass-through `--model`, via the existing `_apply_1m_to_claude_args`)
still wins. `HEADROOM_1M_MODEL` only supplies the fallback when nothing
else is selected. The `[1m]` suffixing and idempotency are unchanged.

Fixes #2937

## Type of Change

- [ ] Bug fix (non-breaking change that fixes an issue)
- [x] New feature (non-breaking change that adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [x] Documentation update
- [ ] Performance improvement
- [ ] Code refactoring (no functional changes)

## Changes Made
- `docs/content/docs/configuration.mdx`: document `HEADROOM_1M_MODEL`
(new "Claude 1M context window" subsection covering `--1m` resolution
order and `[1m]` acceptance) and register it in the Environment
Variables catalog with its current default.
- `tests/test_cli/test_wrap_helpers.py`: assert the knob stays
documented and the documented default tracks `_DEFAULT_1M_MODEL`, so it
cannot silently drift.

- `headroom/cli/wrap.py`: add `HEADROOM_1M_MODEL` env override in
`_resolve_1m_model`; bump `_DEFAULT_1M_MODEL` to `claude-opus-5`.
- `tests/test_cli/test_wrap_helpers.py`: env override wins the fallback;
an explicit current model still wins over the env; blank env falls back
to the built-in; env value is idempotent for an already-`[1m]` value.
Updated the existing "falls back to default" test to assert against the
constant (robust to future bumps) and to clear the env var.

## Testing

- [x] Unit tests pass (`pytest`)
- [x] Linting passes (`ruff check`)
- [x] Type checking passes (`mypy`)
- [x] New tests added

### Test Output

```text
tests/test_cli/test_wrap_helpers.py -k "resolve_1m or apply_1m"  11 passed
tests/test_cli/test_wrap_claude_vertex_proxy_env.py -k 1m         4 passed
# uvx ruff@0.15.22 check  -> All checks passed!
# uvx mypy@1.20.2 headroom/cli/wrap.py -> Success: no issues found in 1 source file
```

## Real Behavior Proof

- Environment: Windows 11, Python 3.12.11, project venv, pytest 9.1.1,
ruff 0.15.22 and mypy 1.20.2 via uvx.
- Exact command / steps: exercised `_resolve_1m_model` directly with the
env var set/unset. With `HEADROOM_1M_MODEL=claude-opus-9` and no
`ANTHROPIC_MODEL`, `--1m` resolves to `claude-opus-9[1m]`; with the env
var unset it resolves to `claude-opus-5[1m]`; a set `ANTHROPIC_MODEL`
(e.g. `claude-sonnet-5`) still wins as `claude-sonnet-5[1m]`.
- Observed result: operators can point `--1m` at the current Opus
without a code change and without pinning `ANTHROPIC_MODEL` globally,
and a fresh install no longer silently opts `--1m` into the previous
generation.
- Not tested: a live Claude Code 1M session (no entitled account here).
The resolution is verified at the helper the launch path uses.

## Runtime Rollout Safety

- Rollout-managed feature(s): none. `wrap claude --1m` model resolution
is a launch-time CLI helper, not a rollout-channel-gated runtime
feature.
- Minimum rollout channel: N/A (no rollout-managed behavior).
- Stable/default behavior changed: yes, narrowly. The built-in `--1m`
fallback default moves from `claude-opus-4-8` to `claude-opus-5` only
when neither `HEADROOM_1M_MODEL` nor `ANTHROPIC_MODEL` is set; any
explicit selection is unaffected.
- Kill switch / disable path: set `HEADROOM_1M_MODEL` (or
`ANTHROPIC_MODEL`) to pin any model; both override the default.
- Unsafe override required: no.
- Qualification impact: none. No proxy request path, routing, or token
accounting is touched.
- Rollback path: revert this PR, or set
`HEADROOM_1M_MODEL=claude-opus-4-8` to restore the prior default without
a code change.

## Review Readiness

- [x] I have performed a self-review
- [x] This PR is ready for human review

## Checklist

- [x] My code follows the project's style guidelines
- [x] I have performed a self-review of my code
- [x] I have commented my code, particularly in hard-to-understand areas
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective
- [x] New and existing unit tests pass locally with my changes
- [x] I did **not** edit `CHANGELOG.md`: it is generated by
release-please from my Conventional Commit PR title

## Additional Notes

The default bump (`claude-opus-4-8` -> `claude-opus-5`) is the second
half of the issue's request. If you would rather keep the constant and
ship only the env override, I can drop that one line; the override alone
already lets operators avoid the stale default.

---------

Co-authored-by: JD Davis <mxjerrett@gmail.com>
2026-08-16 15:09:46 -07:00
..
app docs: improve discoverability for AI agents and search crawlers 2026-05-13 17:36:06 -07:00
components docs: sync Vercel docs with current code and add in-depth proxy config (#2475) 2026-07-21 16:26:56 -07:00
content/docs feat(wrap/claude): make the --1m fallback model configurable via HEADROOM_1M_MODEL (#2983) 2026-08-16 15:09:46 -07:00
lib docs: sync Vercel docs with current code and add in-depth proxy config (#2475) 2026-07-21 16:26:56 -07:00
overrides fix: repair release and docs pipelines 2026-04-16 12:53:51 -05:00
screenshots Merge pull request #147 from JerrettDavis/feat/anthropic-usage-insights 2026-04-12 10:54:22 -07:00
.gitignore new docs UI + ts doc coverage 2026-04-12 13:15:58 +06:00
bun.lock fix(deps): remediate dependency CVEs and publish SBOM (#1509) 2026-06-27 15:28:12 -07:00
claude-code-bedrock-headroom.md fix(bedrock): route ARNs via converse, named AWS profiles, and au. re… (#1456) 2026-07-02 22:51:05 -05:00
context-mode-integration-analysis.md perf(proxy): bound upstream calls and hot-path costs (#2852) 2026-08-09 16:24:33 -07:00
next.config.mjs new docs UI + ts doc coverage 2026-04-12 13:15:58 +06:00
observability.md fix(proxy/metrics): cap client-supplied model label cardinality (#2480) 2026-08-12 00:15:49 -05:00
package-lock.json deps: bump postcss from 8.5.19 to 8.5.26 in /docs (#2881) 2026-08-10 17:30:15 -05:00
package.json deps: bump postcss from 8.5.19 to 8.5.26 in /docs (#2881) 2026-08-10 17:30:15 -05:00
platform-feature-matrix.json fix: harden persistent install startup (#1851) 2026-07-10 00:40:34 -04:00
platform-stabilization.md fix: harden persistent install startup (#1851) 2026-07-10 00:40:34 -04:00
postcss.config.mjs new docs UI + ts doc coverage 2026-04-12 13:15:58 +06:00
proxy.ts new docs UI + ts doc coverage 2026-04-12 13:15:58 +06:00
README.md new docs UI + ts doc coverage 2026-04-12 13:15:58 +06:00
source.config.ts docs(ci): add CI/CD flow diagrams (#1062) 2026-06-16 23:05:15 -07:00
tsconfig.json new docs UI + ts doc coverage 2026-04-12 13:15:58 +06:00
vercel.json fix: add Vercel deploy config and workflow for docs site (#1739) 2026-07-14 13:25:18 -04:00

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