@promptspend/mcp
LLM pricing for coding agents — every price carries its source and the date it
was last confirmed.
There are already MCP servers that will tell you what a model costs. This one
tells you where the number came from, when it was last checked, and which numbers
two sources disagree about. And it will cost a described workload rather than
just quoting a rate, because the arithmetic between "$3 per million tokens" and
"$4,955 a month" is where nearly every estimate goes wrong.
claude mcp add promptspend -- npx -y @promptspend/mcp
No API key. No account. MIT.
Why another pricing server
Every price comes with its paperwork.
{
"model": "gpt-5",
"input_per_million_usd": 1.25,
"output_per_million_usd": 10,
"provenance": {
"source": "vendor",
"source_description": "Hand-verified against the provider's own published pricing page.",
"last_verified": "2026-08-03",
"disputed": false,
"upstream_stale": false,
"confidence": "Confirmed against the provider's own pricing page on 2026-08-03.",
"verified_url": "https://developers.openai.com/api/docs/pricing",
},
}
last_verified moves as rows are re-read, so the date here will age; the shape
will not. What is worth checking is that the block is present at all — a price
without one is a price you cannot audit.
That matters more to an agent than to a person. Someone reading a web page sees
the interface around the number and forms their own view of how much to trust it.
A model handed a bare figure has nothing, and will repeat it with whatever
confidence the phrasing implies. Given the date and the source it can say "as of
1 August, per OpenAI's pricing page" instead of stating a number as though it
were timeless.
And it says when it does not know. Where two sources disagree and no human
has adjudicated, the response is marked disputed: true with both figures,
rather than quietly picking one:
DISPUTED — two sources disagree on this price and no human has adjudicated it.
The figure shown is the primary feed's number, last confirmed 2026-08-02.
Treat it as indicative and say so.
estimate_cost runs promptspend.com's own cost
engine — imported, not reimplemented, so a number this server reports and a
number the website shows cannot drift apart. A test asserts it.
It accounts for the things hand-rolled estimates miss:
- Conversation history compounds. Turn N re-sends turns 1…N−1 as input,
so cost grows with the square of the turn count.
- Cache writes cost more than input — 1.25× at both OpenAI and Anthropic.
Counting only the cheaper reads reports a saving your invoice will not have.
- Long-context tiers apply per request, not per conversation.
- Reasoning tokens are billable even though you never see them.
- Output is priced separately, typically 3–5× input.
"What would a support assistant cost at 4,000 conversations a day on GPT-5
versus DeepSeek V3.2?"
MCP tool definitions are loaded into your context on every turn, for as long
as the server is connected. A heavy server can add thousands of tokens to every
message, which is why the advice going round is to prefer a CLI for read-only
data.
A pricing server that quietly taxes every turn, to tell you about token costs,
would be an easy and deserved joke. So:
This server adds ~700 tokens per turn. Three tools, short descriptions,
budgeted at 900 and checked in CI by npm run check:footprint.
If that number ever stops being true, the build fails — the README figure is
asserted against the actual manifest, not typed once and trusted.
| Tool | What it answers |
|---|
get_price | What does this model cost, and how much should I trust that? |
estimate_cost | What will my workload actually cost per month on each? |
find_cheaper | What could I test that is cheaper and not obviously worse? |
find_cheaper returns candidates to test, never a recommendation — the
capability index behind it is an illustrative estimate, not a benchmark, and the
response says so.
Install
Claude Code
claude mcp add promptspend -- npx -y @promptspend/mcp
Cursor / Claude Desktop / Windsurf — in mcp.json:
{ "mcpServers": { "promptspend": { "command": "npx", "args": ["-y", "@promptspend/mcp"] } } }
What it will not do
- It will not pass off a stale price as current. The catalog is fetched,
never bundled. A retained copy may be used for at most 24 hours when the live
file cannot be reached, and every affected tool response carries an explicit
catalog_status warning written for the agent to relay. Past that bounded
grace period, the tools return an error rather than an old number.
- It has no benchmarks, latency or endpoint data. Other servers do. Three
tools is a deliberate choice about your context budget.
- It has no telemetry. The server itself reports nothing about you, and
needs no key and no account — the same as the API
it reads.
Scope of the prices
Standard-tier, global-endpoint list prices in USD. Not modelled: regional and
data-residency premiums, priority tiers, server-side tool-call fees, fine-tuning,
and negotiated or committed-use discounts.
The same catalog is also in free native apps for
iPhone and iPad and
Android.
Part of PromptSpend — MIT.
Found a wrong price? That is the most serious class of bug this project can have.
Open an issue.