Pricing model

All costs in claudex are approximate. They come from published per-model pricing tiers applied to the token-usage blocks recorded in each session — or, for providers that report their own cost, from that figure directly.

Source of truth: crates/claudex/src/types.rs, ModelPricing::for_model.

Anthropic (Claude) tiers

Each Claude family carries one or more rate cards: Fable 5 sits above Opus as the frontier tier, the current Opus 4.5+ generation is priced well below older Opus models, fast-mode Opus carries a premium, and the original Claude 3 Haiku is cheaper still — so claudex routes each to a dedicated branch.

Model tier	Input	Output	Cache write	Cache read
Fable 5 / Mythos 5	$10.00 / MTok	$50.00 / MTok	$12.50 / MTok	$1.00 / MTok
Opus 4.5+ (4.5–4.8)	$5.00 / MTok	$25.00 / MTok	$6.25 / MTok	$0.50 / MTok
Opus fast (4.6/4.7)	$30.00 / MTok	$150.00 / MTok	$37.50 / MTok	$3.00 / MTok
Opus 4.8 fast	$10.00 / MTok	$50.00 / MTok	$12.50 / MTok	$1.00 / MTok
Opus (legacy 3/4)	$15.00 / MTok	$75.00 / MTok	$18.75 / MTok	$1.50 / MTok
Sonnet (default)	$3.00 / MTok	$15.00 / MTok	$3.75 / MTok	$0.30 / MTok
Haiku 4.5 (latest)	$1.00 / MTok	$5.00 / MTok	$1.25 / MTok	$0.10 / MTok
Haiku 3.5 (legacy)	$0.80 / MTok	$4.00 / MTok	$1.00 / MTok	$0.08 / MTok
Haiku 3	$0.25 / MTok	$1.25 / MTok	$0.3125 / MTok	$0.025 / MTok

(MTok = million tokens. These are Anthropic's published rates.)

OpenAI (gpt-*) tiers

OpenAI models carry many sub-tiers. claudex matches the most specific name first, falling back to a base gpt-5 / gpt-4o rate. For OpenAI models the cache-write rate equals the input rate, and the cache-read rate is the posted "cached input" rate.

Model match	Input	Output	Cache read
gpt-5.5-pro, gpt-5.4-pro	$30.00 / MTok	$180.00 / MTok	$30.00 / MTok
gpt-5-pro	$15.00 / MTok	$120.00 / MTok	$15.00 / MTok
gpt-5.5	$5.00 / MTok	$30.00 / MTok	$0.50 / MTok
gpt-5.4	$2.50 / MTok	$15.00 / MTok	$0.25 / MTok
gpt-5.4-mini	$0.75 / MTok	$4.50 / MTok	$0.075 / MTok
gpt-5.4-nano	$0.20 / MTok	$1.25 / MTok	$0.02 / MTok
gpt-5.3-codex, gpt-5.2-codex, gpt-5.2	$1.75 / MTok	$14.00 / MTok	$0.175 / MTok
gpt-5 (base / other gpt-5*)	$1.25 / MTok	$10.00 / MTok	$0.125 / MTok
gpt-4.1	$2.00 / MTok	$8.00 / MTok	$0.50 / MTok
gpt-4.1-mini	$0.40 / MTok	$1.60 / MTok	$0.10 / MTok
gpt-4.1-nano	$0.10 / MTok	$0.40 / MTok	$0.025 / MTok
gpt-4.5-preview	$75.00 / MTok	$150.00 / MTok	$37.50 / MTok
gpt-4o-mini	$0.15 / MTok	$0.60 / MTok	$0.075 / MTok
gpt-4o-2024-05-13	$5.00 / MTok	$15.00 / MTok	$5.00 / MTok
gpt-4-turbo, gpt-4-1106, gpt-4-0125	$10.00 / MTok	$30.00 / MTok	$10.00 / MTok
gpt-4-32k	$60.00 / MTok	$120.00 / MTok	$60.00 / MTok
gpt-4 (classic 8k / 0613)	$30.00 / MTok	$60.00 / MTok	$30.00 / MTok
gpt-4o (base / other gpt-4*)	$2.50 / MTok	$10.00 / MTok	$1.25 / MTok

(OpenAI tiers are list rates and approximate. The classic GPT-4 / Turbo / 32k tiers predate prompt caching, so their cache-read rate falls back to the input rate. Pi-reported sessions use Pi's own cost instead — see below.)

Tier detection

The tier is chosen by substring-matching the model name, most specific first:

• fable / mythos → the Fable 5 frontier tier ($10/$50).
• opus-4-5–4.8 + fast → the fast-mode premium card ($30/$150 on 4.6/4.7, $10/$50 on 4.8).
• opus-4-5/4.6/4.7/4.8 → Opus 4.5+ rates; any other opus → legacy Opus.
• haiku-4-5 → Haiku 4.5; 3-haiku (but not 3-5-haiku) → the cheapest Claude 3 Haiku tier; any other haiku → Haiku 3.5 legacy.
• gpt-5* / gpt-4* → the matching OpenAI row above (specific variants — including gpt-4-turbo/-32k and classic gpt-4 — win over the gpt-4o base rate).
• sonnet, or a missing/empty model id (old Claude transcripts) → Sonnet.
• Anything else — local, open-weight, and unrecognized models (including Claude's <synthetic>) → $0, unless the provider reported its own cost (see below). This avoids fabricating Sonnet charges for Ollama/MLX/vLLM-style models.

So claude-fable-5 maps to Fable 5 ($10/$50), claude-opus-4-8 maps to Opus 4.5+ ($5/$25), an older claude-opus-3 maps to legacy Opus ($15/$75), and unrecognized names are not charged. Note that the display family label (models command) is just Fable/Mythos/Opus/Haiku/ Sonnet/GPT-5/GPT-4/etc. — it does not distinguish latest from legacy (or fast from standard), but the cost does.

Provider-supplied cost

Pi computes a cost for every assistant message (and reports $0 for local Ollama models), and OpenClaw records a running total per trajectory. claudex trusts those figures rather than re-deriving them from the tier table — so a Pi or OpenClaw session's cost reflects exactly what the provider billed, including free local inference. Internally this is ModelSessionStats::embedded_cost, which the index uses in place of cost_for_model when present.

GitHub Copilot

Copilot is subscription-billed by premium requests, not per-token USD, so claudex prices Copilot CLI sessions from the rate card like Claude/Codex — the USD figure is an API-equivalent estimate of what the same tokens would cost at list price, not what GitHub billed. The premium-request count is preserved in the session's extras. VS Code Copilot Chat stores no token counts locally (they live server-side), so copilot-vscode sessions report zero tokens and $0 cost while still counting for activity, search, and model reports.

Repricing existing data

Every token_usage row records a cost_source: computed (priced from the tiers above) or provider (a figure the provider reported — Pi and OpenClaw today). The binary also carries a PRICING_REVISION that is bumped whenever the rate card changes. On the next run after an upgrade, claudex reprices every computed row in place with the current tiers and stamps the new revision, so the one-off pass runs exactly once. provider rows are never touched, so provider-billed figures (including $0 local models) are preserved.

This is the non-destructive counterpart to claudex index --force: that command deletes and rebuilds from disk and so cannot recover archived/retained sessions, whereas the reprice updates retained rows too. No action is required — new and existing indexes converge on the same rates automatically.

Computation

For each (session, model) row in the token_usage table, when no provider-supplied cost is present:

cost = (input  × input_per_mtok
      + output × output_per_mtok
      + cache_write × cache_write_per_mtok
      + cache_read  × cache_read_per_mtok) / 1_000_000

For Codex, input/cache_read come from the last cumulative token_count record (the cached portion of the prompt is billed as a cache read). Sessions that switched models accumulate multiple rows; totals sum across them.

Why it's approximate

• No volume discounts. Priority throughput, batch pricing, etc. aren't reflected.
• No historical pricing. If tiers change, old sessions are priced at current rates. Claudex doesn't store a rate card.
• No free tier / promo credits. These are invoicing concerns; they don't show up in the API response.
• Cache-read estimate. Cache reads don't always correspond to billable tokens 1:1 in every context. Claudex prices them at the posted rate, which is a close upper bound.

For authoritative billing, use Anthropic's console. Claudex is for relative comparisons — "which project costs more", "which model tier am I leaning on", "how does this week compare to last" — where the model-agnostic math is accurate enough.

Opus:Sonnet ratio

Legacy Opus is exactly 5× Sonnet on every dimension ($15 vs $3 input, $75 vs $15 output, etc.). Current Opus 4.5+ is much cheaper — $5/$25 input/output, roughly 1.7× Sonnet — so do not assume a 5× multiple for present-day Opus sessions. If an Opus cost looks lower than you expect, that's usually the 4.5+ rate card, not an error; mid-session model switching can also lower it.

Rendering

• fmt_cost renders $12,345.67 with thousands separators.
• Values below one cent fall back to four decimals: $0.0042. Tiny sessions don't disappear into $0.00.
• JSON output always uses raw cost_usd floats — no formatting.