Commit graph

6 commits

Author SHA1 Message Date
Abhay Singh
b4f807f21a
fix(proxy/cost): price cache savings by most-used model, not first-seen (#2023)
## Description

`build_prefix_cache_stats` (`headroom/proxy/cost.py`) values each
provider's cache-read savings
using a single "base input price per token". It derives that price by
scanning
`cost_tracker._tokens_sent_by_model` and **breaking on the first**
provider-matching model that
has a price — even though the comment says "most-used model":

```python
# Get the base input price per token for the most-used model on this provider
input_price_per_token = None
if cost_tracker:
    for model_name in cost_tracker._tokens_sent_by_model:   # insertion order, NOT usage order
        ...
        if is_match:
            price_per_1m = cost_tracker._get_list_price(model_name)
            if price_per_1m:
                input_price_per_token = price_per_1m / 1_000_000
                break                                        # first match wins
```

`_tokens_sent_by_model` is insertion-ordered, so the price used depends
on which model was
*recorded first*, not on usage volume. A Claude Code session sends both
Sonnet (main loop) and
Haiku (titles/subagents). If Haiku ($0.80/M) was seen before Sonnet
($3/M), **all** of the
provider's cache-read savings are priced at Haiku's rate — understating
the dashboard's cache
savings by ~3.75×. Reverse the order and it overstates.

Closes: no issue filed — found while auditing the cache-savings pricing.

## Fix

Pick the provider-matching, priced model with the **highest token
volume** instead of breaking
on the first match:

```python
best_tokens = -1
for model_name, tokens_sent in cost_tracker._tokens_sent_by_model.items():
    if is_match and tokens_sent > best_tokens:
        price_per_1m = cost_tracker._get_list_price(model_name)
        if price_per_1m:
            input_price_per_token = price_per_1m / 1_000_000
            best_tokens = tokens_sent
```

## Type of Change

- [x] Bug fix (non-breaking change that fixes an issue)

## Changes Made

- `headroom/proxy/cost.py`: select the highest-volume provider-matching
model (with a known price) rather than the first-recorded one.
- `tests/test_proxy_cache_ttl_metrics.py`: add
`test_prefix_cache_stats_prices_by_most_used_model` using real distinct
per-model prices. (The existing cache-stats tests monkeypatch
`_get_list_price` to a constant `100.0`, which masked the
model-selection logic — hence the bug slipped through.)

## Testing

- [x] New regression test added
(`tests/test_proxy_cache_ttl_metrics.py`)
- [x] Linting/formatting clean — run with the CI-pinned `ruff==0.15.17`
- [ ] Full `pytest` deferred to CI (local-OOM reason below).

```text
$ uvx ruff@0.15.17 check headroom/proxy/cost.py tests/test_proxy_cache_ttl_metrics.py
All checks passed!
```

## Real Behavior Proof

- Environment: Windows 11, Python 3.10, headroom from this branch.
Importing `headroom` pulls in the torch/transformers stack and a full
`pytest` gets OOM-killed on this box, so I verified the selection logic
with a dependency-free script and left the full pytest to CI.
- Exact command / steps: ran a `{haiku: 500, sonnet: 50000}` token map
(Haiku recorded first, Sonnet the higher volume) through both the old
first-match and new highest-volume selection with real prices.
- Observed result: the old logic picks Haiku's $0.80/M (first-inserted);
the new logic picks Sonnet's $3/M (highest volume) and is
insertion-order independent:

```text
OLD picks Haiku price: 0.80/M  (first-inserted)
NEW picks Sonnet price: 3.00/M  (highest volume)
  -> old understates the input price by 3.75x (3.75x)
NEW is insertion-order independent
COST MOST-USED-MODEL FIX VERIFIED
```

- Not tested: rendering the live dashboard (needs the running app). The
fix is confined to the price-selection loop and the new test drives
`build_prefix_cache_stats` directly. Full local `pytest` deferred to CI
(OOM, per above).

## 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
- [ ] 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 or that my
feature works
- [ ] New and existing unit tests pass locally with my changes — ran
lint + a standalone logic check; full pytest deferred to CI (local OOM,
disclosed above)
- [x] I have updated the CHANGELOG.md if applicable

## Additional Notes

- No new dependencies; a single-loop change plus a test with realistic
prices.
- @JerrettDavis tagging you — this skews the dashboard's per-provider
cache-savings dollar figure by the ratio between a provider's models
(≈3.75× for Sonnet/Haiku), so it seemed worth surfacing. Thanks!

---------

Co-authored-by: JerrettDavis <mxjerrett@gmail.com>
Co-authored-by: Tejas Chopra <chopratejas@gmail.com>
2026-07-13 09:37:58 -04:00
Rod Boev
53a465b121
fix(proxy): subtract cache write premiums from net savings (#1800)
## Description

Cache stats already calculate both prompt-cache read savings and
cache-write premium cost, but the exported `net_savings_usd` field used
gross read savings alone. That made cache-heavy token-mode workloads
look profitable even when extra cache writes offset or exceeded the read
discount. This updates existing cache cost accounting so provider and
total `net_savings_usd` subtract write premiums while keeping gross
savings and write premium fields visible. Refs #327.

The scope follows doublefx's controlled measurement in
https://github.com/headroomlabs-ai/headroom/issues/327#issuecomment-4683604089,
which showed token-mode compression increasing cache write volume and
billed cost while dashboard token savings looked positive.

## Type of Change

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

## Changes Made

- Subtract cache write premiums from provider-level cache
`net_savings_usd`.
- Subtract aggregate cache write premiums from total cache
`net_savings_usd`.
- Keep gross `savings_usd` and `write_premium_usd` visible for dashboard
and telemetry consumers.
- Add focused regressions for provider net, total net, and
zero-write-premium preservation.
- Update the dashboard cache TTL fixture to match the corrected net
value.

## Testing

- [x] Unit tests pass (`uv run pytest
tests/test_proxy_cache_ttl_metrics.py
tests/test_dashboard_cache_ttl_playwright.py
tests/test_proxy_dashboard_stats_cache.py -q`)
- [x] Linting passes (`uv run ruff check headroom/proxy/cost.py
tests/test_proxy_cache_ttl_metrics.py
tests/test_dashboard_cache_ttl_playwright.py
tests/test_proxy_dashboard_stats_cache.py`)
- [ ] Type checking passes (`uv run mypy headroom`)
- [x] New tests added for new functionality when applicable
- [x] Manual testing performed

### Test Output

```text
uv run pytest tests/test_proxy_cache_ttl_metrics.py tests/test_dashboard_cache_ttl_playwright.py tests/test_proxy_dashboard_stats_cache.py -q
28 passed, 2 skipped, 1 warning in 32.75s

uv run pytest tests/test_proxy_cache_ttl_metrics.py -q -k keeps_net_equal_without_write_premium
1 passed, 16 deselected in 0.15s

uv run ruff check headroom/proxy/cost.py tests/test_proxy_cache_ttl_metrics.py tests/test_dashboard_cache_ttl_playwright.py tests/test_proxy_dashboard_stats_cache.py
All checks passed!
```

## Real Behavior Proof

- Environment: Windows, Python through the project `uv` environment.
- Exact command / steps: run the cache net-savings regressions against
base and head.
- Observed result: base reports provider net as `0.0036` instead of
`0.0021` and total net as `0.0046` instead of `0.0031`; head passes the
focused cache metrics suite and preserves `net_savings_usd ==
savings_usd` when there is no write premium.
- Not tested: broader cache-hit-rate tuning, prompt-cache policy
changes, and live provider billing.

## 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 or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [x] I have updated the CHANGELOG.md if applicable

## Additional Notes

No changelog entry is needed because this corrects existing stats fields
rather than adding a new command or control. Type checking was not part
of the focused local validation for this Python-only fix. Dashboard
Playwright coverage is CI-owned locally; the import-gated file was
included in the focused pytest command and skipped because Playwright is
not installed in this environment.
2026-07-07 23:24:41 -05:00
Vinay Gupta
5fe4e7b195
fix(proxy): expose persistent savings metrics (#1647)
## Description

Closes #1616

Expose the proxy's durable `persistent_savings.lifetime` totals through
`/metrics` so Prometheus/Grafana scrapes can read the same lifetime
savings counters already visible in `/stats` and `/stats-history`.

The existing runtime counters remain process-local:
`headroom_tokens_saved_total` still resets with the proxy process. New
`headroom_persistent_savings_*` counters are sourced from the
`SavingsTracker` lifetime block.

## Type of Change

- [x] Bug fix (non-breaking change that fixes an issue)
- [ ] 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

- Export durable lifetime savings counters from
`PrometheusMetrics.export()`:
  - `headroom_persistent_savings_requests_total`
  - `headroom_persistent_savings_tokens_saved_total`
  - `headroom_persistent_savings_input_tokens_total`
  - `headroom_persistent_savings_input_cost_usd_total`
  - `headroom_persistent_savings_compression_savings_usd_total`
- Add a restart regression proving runtime counters reset while
persistent savings counters remain available from the same savings file.
- Extend the existing `/stats-history` restart test with `/metrics`
endpoint assertions.
- Update metrics docs to distinguish runtime
`headroom_tokens_saved_total` from lifetime
`headroom_persistent_savings_tokens_saved_total`.

## Testing

- [x] Unit tests pass (`pytest`)
- [x] Linting passes (`ruff check .`)
- [ ] Type checking passes (`mypy headroom`)
- [x] New tests added for new functionality
- [x] Manual testing performed

### Test Output

```text
Local focused checks:
$ rtk /usr/bin/env HEADROOM_REQUIRE_RUST_CORE=false PYTHONPATH=. /tmp/headroom-1616-testenv/bin/python -m pytest tests/test_proxy_cache_ttl_metrics.py::test_prometheus_metrics_export_includes_extended_fields tests/test_proxy_cache_ttl_metrics.py::test_prometheus_export_includes_persistent_savings_after_restart
2 passed, 1 warning in 0.19s

$ rtk /tmp/headroom-1616-testenv/bin/python -m ruff check headroom/proxy/prometheus_metrics.py tests/test_proxy_cache_ttl_metrics.py tests/test_proxy_savings_history.py
All checks passed!

$ rtk /tmp/headroom-1616-testenv/bin/python -m ruff format --check headroom/proxy/prometheus_metrics.py tests/test_proxy_cache_ttl_metrics.py tests/test_proxy_savings_history.py
3 files already formatted

$ rtk git diff --check
# no output

GitHub Actions:
All non-skipped checks passed on PR #1647, including lint, build, build-wheel, test (1-4), test-agno, test-extras, test-dashboard-ui, docker-native-e2e, docker-init-e2e, docker-wrap-e2e, security checks, merge-conflicts, and PR governance.
```

## Real Behavior Proof

- Environment: local macOS worktree, throwaway Python env at
`/tmp/headroom-1616-testenv`, `PYTHONPATH=.`.
- Exact command / steps: recorded a compressed request through
`PrometheusMetrics.record_request()`, re-created `PrometheusMetrics`
with the same `SavingsTracker` path, then exported `/metrics` text.
- Observed result: runtime counters are zero after re-creating the
metrics object, while `headroom_persistent_savings_tokens_saved_total`
and related persistent counters still expose the durable lifetime
values.
- Not tested: full server-level pytest locally, because the local build
is blocked by the known native `headroom._core`/`esaxx-rs` build issue
(`fatal error: 'cstdint' file not found`). The app-level `/metrics`
assertions passed in GitHub Actions.

## 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
- [ ] 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 or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [ ] I have updated the CHANGELOG.md if applicable

## Screenshots (if applicable)

N/A

## Additional Notes

This intentionally does not rename or hydrate the existing runtime
`headroom_tokens_saved_total` counter. That preserves the current
process-local semantics and gives external dashboards a dedicated
lifetime series that maps directly to `/stats.persistent_savings`.

`mypy headroom` was not run as a standalone local command. CHANGELOG is
N/A for this narrow proxy metrics fix unless maintainers prefer an
entry.
2026-07-01 23:28:12 -05:00
Lakshya Sharma
4658721ea0
feat(cache): attribute prompt-cache misses to TTL lapse vs prefix change (#1313) (#1343)
## Description

A low prompt-cache hit rate is hard to act on without knowing *why*
turns miss. Two very different causes need very different responses:

- **TTL lapse** — the session went idle longer than the provider's cache
lifetime, so the entry expired. The fix is a longer TTL (e.g.
Anthropic's 1h breakpoint instead of the 5m default).
- **Prefix change** — the cacheable message prefix shifted, so the new
request couldn't match the cached key. A longer TTL won't help here at
all.

Right now those look identical from the dashboard (just "cache_read was
0"). This adds the attribution so a user can actually decide 5m vs 1h.

Closes #1313

## 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)
- [ ] Documentation update
- [ ] Performance improvement
- [ ] Code refactoring (no functional changes)

## Changes Made

`PrefixCacheTracker` already kept the previous turn's forwarded messages
and a per-turn activity timestamp, so the signal was already there — it
just wasn't being read.

- **`prefix_tracker.py`** — `classify_cache_miss()`: when a turn
expected a cached prefix (non-zero cached tokens last turn) but read 0
this turn, returns `ttl_expiry` if the idle gap exceeded the provider
cache TTL, else `prefix_change` if the forwarded prefix differs from
last turn's, else `unknown`. **TTL wins ties** — once the entry lapsed,
a coincident content change is moot, and the 5m-vs-1h decision is
exactly what the TTL signal answers. A 1h-breakpoint session can widen
the window via `PrefixFreezeConfig.cache_ttl_seconds`. Cold starts and
hits return `is_miss=False`.
- **Anthropic handlers (streaming + non-streaming)** — classify BEFORE
`update_from_response` overwrites the last-turn state the classifier
reads, then record the reason.
- **`prometheus_metrics.py`** — a per-provider/per-reason counter,
`record_cache_miss_attribution()`, reset handling, and a
`headroom_cache_miss_attribution_total{provider,reason}` export series.
- **`cost.py`** — `build_prefix_cache_stats()` aggregates a
`miss_attribution` block (per-provider + totals, with the ttl/prefix
split as a % of *attributed* misses, so `unknown` doesn't dilute the
headline).
- **dashboard** — a "Cache Miss Attribution" panel (TTL expiry / prefix
change / unknown / total) with a "mostly TTL lapse" vs "mostly prefix
change" headline.

Scoped to Anthropic for this first cut (where the tracker is fully
wired); OpenAI/Gemini can follow once the shape is proven.

## Testing

- [x] Unit tests pass (`pytest`)
- [ ] Linting passes (`ruff check .`)
- [ ] Type checking passes (`mypy headroom`)
- [x] New tests added for new functionality
- [ ] Manual testing performed

### Test Output

```text
$ python -m pytest tests/test_cache/test_prefix_tracker.py -q
38 passed
# 29 existing + 9 new classifier tests (TestClassifyCacheMiss).

$ python -m pytest tests/test_proxy_cache_ttl_metrics.py -k "miss_attribution or reset_runtime_clears" -q
5 passed, 8 deselected
# new: counter bucketing, stats aggregation, empty case, /metrics export, reset.
```

The full `test_proxy_cache_ttl_metrics.py` /
`test_proxy_dashboard_stats_cache.py` files have some failures in this
sandbox (`test_stats_endpoint_*`, streaming-parser, reset-counters) —
those spin up the proxy server / Rust `_core` extension, which isn't
built here. I confirmed via `git stash` that they fail identically on
`main` without my changes, so they're pre-existing and unrelated. My
additions to the stats dict are purely additive and don't break any
passing assertion.

## Real Behavior Proof

- Environment: Windows 11, Python 3.10. The Rust `_core` extension and a
live proxy aren't available in this checkout.
- Exact command / steps: drove `classify_cache_miss()` through every
branch with a faithful warm-then-miss sequence; drove
`record_cache_miss_attribution()` → `build_prefix_cache_stats()` →
`export()` end to end.
- Observed result: classifier returns
`cold_start`/`hit`/`ttl_expiry`/`prefix_change`/`unknown` correctly, TTL
wins the tie when both signals fire, a growing (append-only) prefix is
treated as stable, and the 1h override widens the window. The stats
builder produces `miss_attribution.totals`
(`ttl_expiry`/`prefix_change`/`unknown`/`total` +
`ttl_expiry_pct`/`prefix_change_pct` over attributed misses) and
`by_provider`; `/metrics` emits
`headroom_cache_miss_attribution_total{provider="anthropic",reason="ttl_expiry"}`.
- Not tested: a live Anthropic session through the running proxy with a
real idle-then-resume to confirm the handler wiring fires end-to-end. I
verified the handler integration by reading scope/order (classify before
`update_from_response`, `provider_name`/`self.metrics` in scope) and
unit-tested every layer it calls, but didn't exercise the actual server
loop.

## 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
- [ ] 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 or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [ ] I have updated the CHANGELOG.md if applicable

## Additional Notes

- The classifier is intentionally pure (takes the cache-read result +
current forwarded messages + an optional idle override) so it's
order-independent and unit-testable without a live tracker clock.
- No README/docs change yet — this surfaces in the dashboard and
`/metrics`, which are self-describing; happy to add a docs page if you'd
like one.
- CHANGELOG.md isn't touched — release-please generates it from the
`feat(cache):` commit subject.
- Follow-ups if useful: extend to OpenAI/Gemini handlers, and add a
per-provider breakdown row in the dashboard panel (the stats already
carry `by_provider`).
2026-06-24 09:50:34 -05:00
JerrettDavis
be6aa14110 feat: expose proxy OTEL metrics and Langfuse status
Wire the proxy's operational metrics facade into the new observability
layer, expand built-in Prometheus export, surface OTEL and Langfuse status
in /stats, and document the split between anonymous telemetry, OTEL metrics,
and Langfuse traces.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-04-09 21:20:46 -05:00
JerrettDavis
a6787556be Add observed cache TTL metrics and dashboard coverage 2026-04-06 21:13:30 -05:00