Model Pricing & Cost Attribution

Cost attribution turns gateway token usage into per-team cost. Prices resolve in two layers: a static fallback table baked into the cost-attribution Lambda, and a runtime DynamoDB overlay that overrides it. Custom agreements, volume discounts, and regional uplifts belong in the overlay — never in the code.

How a price resolves

1. The Lambda loads PRICING_TABLE (static defaults) on cold start.
2. If PRICING_TABLE_NAME is set, it scans that DynamoDB table and merges the entries on top of the static table (DynamoDB wins), cached for 5 minutes.
3. get_cost(provider, model, …) looks up (provider, model). A miss logs a WARNING and emits the UnknownModelPrice CloudWatch metric while still returning the _DEFAULT_PRICE estimate — so an unpriced model is visible and alarmable, never silently mis-billed.

So the static table is only a fallback. Anything you put in the overlay takes precedence within 5 minutes, with no redeploy.

Setting custom prices at runtime

Each pricing row is one DynamoDB item:

Attribute	Value
PK	PRICE#{provider}#{model} (e.g. PRICE#bedrock#openai.gpt-5.5)
SK	CONFIG
provider, model	the lookup key
input_per_1k, output_per_1k	USD per 1K tokens
cache_read_per_1k, cache_write_per_1k	optional; omit if the model has no cache discount
cache_supported	optional bool; set false for models with no cache-billing lane (e.g. gpt-oss) so savings report 0 instead of a default 10%-of-input estimate

Manage these through the pricing admin API (/pricing, behind the admin-plane Cognito authorizer) — GET/PUT/DELETE per provider/model. That is the supported path for an operator to record an Epic-specific negotiated rate or a volume tier without touching code.

Note

The pricing overlay table and the pricing_admin Lambda are part of the admin plane (enable_admin_api). Until that is wired, prices come from the static fallback table only. The static defaults are correct published list rates as of their last verification — see the comments in src/cost_attribution/pricing.py for per-model sources and dates.

Verified default rates (fallback)

The static OpenAI-on-Bedrock defaults were verified 2026-06-11 against the AWS Bedrock pricing page and the AWS Price List bulk API:

Model	Input /1K	Output /1K	Cache read /1K	Notes
bedrock / openai.gpt-5.5	$0.0055	$0.033	$0.00055	AWS rate (~10% over OpenAI 1st-party list)
bedrock / openai.gpt-5.4	$0.00275	$0.0165	$0.000275	AWS rate; GovCloud differs
bedrock / openai.gpt-oss-120b	$0.00015	$0.0006	—	no cache lane (cache_supported=false)
bedrock / openai.gpt-oss-20b	$0.00007	$0.0003	—	no cache lane

Caution

AWS bills the OpenAI frontier models ~10% above OpenAI’s first-party list price, and rates vary by region (GovCloud is higher). The numbers above are commercial us-east-1 list rates and are a fallback — set the overlay to your actual billed/negotiated rate for accurate chargeback.

Anthropic Claude on Bedrock (verified 2026-06-11)

Standard (regional) rate on the base model ID; the global.-prefixed inference profile is ~10% cheaper and has its own row. Published cache-read is exactly 10% of input and cache-write (5-min) exactly 125%, so the defaults compute correct cache savings without per-row cache fields.

Model	Base ID	Input /1K	Output /1K
Opus 4.8	anthropic.claude-opus-4-8	$0.0055	$0.0275
Opus 4.7	anthropic.claude-opus-4-7	$0.0055	$0.0275
Opus 4.6	anthropic.claude-opus-4-6-v1	$0.0055	$0.0275
Opus 4.5	anthropic.claude-opus-4-5-20251101-v1:0	$0.0055	$0.0275
Opus 4.1 / 4	anthropic.claude-opus-4-1-... / -4-...	$0.015	$0.075
Sonnet 4.6	anthropic.claude-sonnet-4-6	$0.0033	$0.0165
Sonnet 4.5	anthropic.claude-sonnet-4-5-20250929-v1:0	$0.0033	$0.0165
Sonnet 4	anthropic.claude-sonnet-4-20250514-v1:0	$0.003	$0.015
Haiku 4.5	anthropic.claude-haiku-4-5-20251001-v1:0	$0.0011	$0.0055
Fable 5	anthropic.claude-fable-5	$0.011	$0.055

Note

Model-ID forms are not uniform across the 4.x line — 4.8/4.7 carry no -v1/date, 4.6 has -v1 but no date, 4.5 and older carry the full date — so the table keys on exact strings, not a date-stamp pattern. Haiku exists only at 4.5 in the 4.x line. Claude Mythos 5 (anthropic.claude-mythos-5) is a gated preview with no published price — intentionally omitted so it trips UnknownModelPrice rather than billing at a guess.

Auto-refresh (future)

AWS exposes per-model token pricing programmatically via the Price List bulk API (offer codes AmazonBedrock and AmazonBedrockFoundationModels) and the pricing:GetProducts query API. A scheduled job can refresh the overlay from these rather than hand-editing — but it must tolerate a missing row (the bulk API lags new-model GA) by keeping the last-known rate and alerting, not failing.