## Thinking Path
> - Paperclip is the open source app people use to manage AI agents for
work
> - The heartbeat service is the control plane that runs agents through
adapters and records each run's usage and cost in the finance/cost
ledger
> - Adapters report a provider cost (`costUsd`), but there is no way to
represent the provider-billed cost *after* prompt-cache discounts, so
cache-heavy runs are priced wrong and some paid runs end up exported
with a zero/null cost
> - A benchmark comparing Paperclip-orchestrated runs against direct
harness invocation of the same tasks measured 1.5–3.1× higher apparent
USD per pair, largely because cache-discounted billing was not
represented in the exported cost data
> - This pull request adds an optional `cacheAdjustedCostUsd` field to
`AdapterExecutionResult` and a `resolveCacheAdjustedCostUsd` helper in
the heartbeat service that prefers the explicit cache-adjusted figure
and falls back to the reported `costUsd`, persisting it into the run's
usage/ledger JSON
> - The benefit is that paid runs are no longer exported as zero/null
cost and cache-heavy runs can be priced correctly, so operators
comparing orchestrated vs. direct costs see real numbers
## Linked Issues or Issue Description
No single existing public issue covers this exactly; closely related
cost-reporting issues:
- Refs #8947 — hermes adapter never reports usage/cost to Paperclip, so
budget limits never trigger
- Refs #6716 — hermes_local cost/usage capture returns zero
- Refs #3320 — expose per-run token counts in activity log and dashboard
**Problem (feature-request form):** Adapters can only report a single
`costUsd`. Providers with prompt caching bill less than the nominal
token cost, and the heartbeat cost accounting has no field for the
cache-adjusted billed amount. As a result, cache-heavy paid runs are
either priced at the undiscounted figure or, when the adapter withholds
the ambiguous number, exported as zero/null. **Proposed solution:** an
explicit optional `cacheAdjustedCostUsd` on the adapter execution
result, resolved server-side with a safe fallback to `costUsd`.
**Alternatives considered:** recomputing cache discounts server-side
from token counts (rejected: provider pricing tables drift and cache
billing rules are provider-specific; the adapter is the source of
truth).
## What Changed
- `packages/adapter-utils/src/types.ts`: added optional
`cacheAdjustedCostUsd?: number | null` to `AdapterExecutionResult`, with
a doc comment on adapter expectations
- `server/src/services/heartbeat.ts`: added exported
`resolveCacheAdjustedCostUsd()` (explicit cache-adjusted value wins when
a finite non-negative number; otherwise falls back to a finite
non-negative `costUsd`; otherwise `null`), and consistently uses the
resolved billed value for ledger cents, cost status, and run usage JSON
- `server/src/__tests__/heartbeat-cost-accounting.test.ts`: added unit
coverage for explicit precedence, fallback, invalid values,
adjusted-only pricing, and discounted ledger billing
## Verification
- `pnpm exec vitest run
server/src/__tests__/heartbeat-cost-accounting.test.ts` — 1 file, 7
tests passed
- `pnpm --filter @paperclipai/adapter-utils typecheck` — passed
- `pnpm --filter @paperclipai/server typecheck` — passed
- GitHub Actions on head `dc9c3830bf694b9afb3b27c5c8c36bff38e7fdcb` —
all 26 checks clean/skipped; one unrelated E2E checkout-contention flake
passed on its single failed-job rerun
- Greptile review on the same head — 5/5 with zero unresolved threads
## Risks
- Low risk: the field is optional and additive; when absent, behavior
falls back to the existing `costUsd` path
- Ledger/usage JSON gains a new optional `cacheAdjustedCostUsd` key —
consumers that strictly validate keys would need to tolerate it (usage
JSON is already open-shaped)
- No migrations, no API-breaking changes
> For core feature work, check [`ROADMAP.md`](ROADMAP.md) first and
discuss it in `#dev` before opening the PR. Feature PRs that overlap
with planned core work may need to be redirected — check the roadmap
first. See `CONTRIBUTING.md`.
## Model Used
- Implementation: Anthropic Claude Fable 5, model ID `claude-fable-5`,
standard context window, agentic coding mode with shell/file tool use
- PR preparation and verification: OpenAI Codex on GPT-5 (the runtime
did not expose a more specific serving snapshot or context-window
value), reasoning mode with shell and GitHub tool use
## Checklist
- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have searched GitHub for duplicate or related PRs and linked
them above
- [x] I have either (a) linked existing issues with `Fixes: #` / `Closes
#` / `Refs #` OR (b) described the issue in-PR following the relevant
issue template
- [x] I have not referenced internal/instance-local Paperclip issues or
links (only public GitHub `#NNN` / `github.com/paperclipai/paperclip`
URLs)
- [x] My branch name describes the change (e.g. `docs/...`, `fix/...`)
and contains no internal Paperclip ticket id or instance-derived details
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] I have updated relevant documentation to reflect my changes (doc
comment on the new field; no user-facing docs affected)
- [x] I have considered and documented any risks above
- [x] All Paperclip CI gates are green
- [x] Greptile is 5/5 with no open P2s, recommendations, or follow-ups
- [x] I will address all Greptile and reviewer comments before
requesting merge
---------
Co-authored-by: Paperclip <noreply@paperclip.ing>
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