Fermi

kromatic-innovation/fermi

Takes a natural language question like "Will this feature ship by Q2?" and returns calibrated probability distributions instead of point estimates. Works over both REST and MCP, so you can integrate forecasting into Claude conversations or your own applications. Useful when you need quantified uncertainty rather than binary predictions, like estimating project timelines, evaluating risks, or making decisions under uncertainty. The SSE transport means you can stream probability updates as the model refines its analysis. Reach for this when you want Claude to think probabilistically and give you distributions you can actually use in downstream calculations or decision frameworks.

tools: 6
transport: HTTP
last updated: Oct 28, 2026

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Install

From registry metadata

$ npx add-mcp https://fermi.kromatic.com/mcp --name fermi

Run in your terminal. add-mcp asks which agents to add it to (Claude Code, Codex, Cursor and more). Add -g to install it for every project.

Review the command, arguments and environment values before installing. MCP servers run with your local permissions.

Other ways

Claude Code

$ claude mcp add --transport http fermi https://fermi.kromatic.com/mcp

Run in your terminal. Add --scope user to make it available in every project.

Tools

Verified live · 6 tools

Verified live against the running server on Nov 6, 2026.

estimate_quantity_or_probabilityEstimates an uncertain number, or the probability that an event happens by a date, from a question in plain language, and returns a calibrated range and probability distribution. Use this when the user asks how much, how many, how big or how long something is or will be (marke...12 params

Estimates an uncertain number, or the probability that an event happens by a date, from a question in plain language, and returns a calibrated range and probability distribution. Use this when the user asks how much, how many, how big or how long something is or will be (marke...

Parameters* required

api_keyvalue

Your Fermi API key. Omit it if your connector is already signed in, or to use Fermi without an account. Get one with POST https://fermi.kromatic.com/api/v1/accounts (returned once).

callback_urlvalue

Optional URL that receives the finished or failed result as a signed POST, so a server need not keep asking. Chat clients usually cannot receive it: read the result with get_estimate_result instead.

contextvalue

Anything the estimate should take into account. For a question about the future always include today's date ("Today is 2026-10-30."), plus recent facts or news, and the user's own numbers or defini...

coverage_probabilitynumber

How likely the returned interval is to contain the true value, strictly between 0 and 1. Default 0.9, a 90% interval. Use 0.95 for a "95% interval", 0.8 for an "80% range".default: 0.9

disclaimer_acknowledged*boolean

Must be true. Confirms the result is a probabilistic estimate for decision support, not financial, medical or legal advice. A call with false is refused.

modelvalue

Optional model id for that provider. It must be the model configured for that tier and provider, so normally omit it.

providervalue

Optional AI provider for the estimate, "openai" or "anthropic". Omit to use the default. Tiers 2 and 3 accept only "openai".

question*string

The question in plain language, one quantity or one event per call. Quantity: "How many hotel rooms will Lisbon have in 2030?". Yes/no event: "Will any EU country make a four-day work week law befo...

requested_tier_idinteger

1 = fast: answers in the same call, no web search; the only tier without an account. 2 = grounded: answers in the same call, searches the web; account only. 3 = deep research: runs in the backgroun...default: 1

source_inputsvalue

Optional documents or data for the estimate to use. Each item has source_type ("qualitative_text", "spreadsheet" or "structured_file") and either content (text) or structured_data (an object, or a...

target_horizon*string

When the answer applies. Prefer an absolute date or year: "by 2027-06-30", "2030", "end of 2028", or "current" for a value today. Turn relative phrases like "in the next 12 months" into a date, bec...

unit*string

Unit of the answer, e.g. "USD", "people", "hotel rooms", "days". For a yes/no event question use "probability (0-1)": the answer is then a probability between 0 and 1 (0.15 = 15%).

get_estimate_resultReads one estimate you already requested, by its estimate_id. Use this when a tier-3 (deep research) estimate came back with status "pending" and you want to know whether it is finished, or to show an earlier estimate again. Tier-3 results are only delivered this way (or to a...2 params

Reads one estimate you already requested, by its estimate_id. Use this when a tier-3 (deep research) estimate came back with status "pending" and you want to know whether it is finished, or to show an earlier estimate again. Tier-3 results are only delivered this way (or to a...

Parameters* required

api_keyvalue

The same api_key used when the estimate was requested (omit it if none was used, or if your connector is signed in). Estimates are visible only to the credentials that made them.

estimate_id*string

The estimate_id returned by estimate_quantity_or_probability or listed by list_my_estimates.

list_my_estimatesLists the past estimates on your account, newest first. Use this when the user wants to find an earlier estimate ("what did I estimate last week?") or has lost an estimate_id. Returns estimates, each with estimate_id, created_at, question, unit, target_horizon, point_estimate,...3 params

Lists the past estimates on your account, newest first. Use this when the user wants to find an earlier estimate ("what did I estimate last week?") or has lost an estimate_id. Returns estimates, each with estimate_id, created_at, question, unit, target_horizon, point_estimate,...

Parameters* required

api_keyvalue

Your Fermi API key. Required unless your connector is signed in. Get one with POST https://fermi.kromatic.com/api/v1/accounts.

limitinteger

How many estimates to return, 1 to 100. Default 20.default: 20

offsetinteger

How many of the newest estimates to skip, for paging: pass the previous page's next_offset. Default 0.default: 0

send_feedbackSends a short report about Fermi to the team that builds it. They read every report and use it to fix problems and decide what to build, so honest feedback, good or bad, is useful. Use this when: - a Fermi tool returned an error (send it right away), behaved unexpectedly or ga...13 params

Sends a short report about Fermi to the team that builds it. They read every report and use it to fix problems and decide what to build, so honest feedback, good or bad, is useful. Use this when: - a Fermi tool returned an error (send it right away), behaved unexpectedly or ga...

Parameters* required

api_keyvalue

Optional Fermi API key. If given, the account id is attached so the team can look into it.

error_textvalue

The error code and message the tool returned, if any. Remove any personal data or private context it quotes.

estimate_idvalue

The estimate_id the report is about, if an estimate was involved.

expectedvalue

What you expected to happen instead.

feedback_typestring

What kind of report this is. bug: a tool errored or broke. wrong_result: it ran but the estimate looks wrong. unmet_use_case: the user needed something no tool does. feature_request: a missing opti...one of bug · unmet_use_case · feature_request · confusing · wrong_result · praisedefault: other

impactvalue

How much it cost the user. blocked: could not finish. workaround: finished another way. minor: an annoyance. none: no cost, for example praise.

message*string

The report, in your own words, 10 to 5,000 characters. Say what you tried, what happened and what you expected. Leave out names, companies, the user's numbers or private context, and the conversati...

sender_emailvalue

Optional. The user's email address, only if they want a reply and gave it to you. Do not invent one. No copy is sent to it.

sender_namevalue

The user's name. Optional; only with sender_email.

suggestionvalue

What would have helped: a fix, a new feature or clearer wording.

tool_namevalue

The Fermi tool the report is about, for example estimate_quantity_or_probability.

user_goalvalue

What the user was trying to do, as a general task in a few words, for example "forecast a market size". No names, company names or figures.

what_happenedvalue

What actually happened, in general terms, without the user's numbers.

buy_creditsBuys Fermi credits by charging the card saved on your account, and returns the new balance. Use this when the user explicitly asks to buy or top up Fermi credits. Returns credits_purchased, new_balance and payment_status. If no card is saved yet, nothing is charged: it returns...2 params

Buys Fermi credits by charging the card saved on your account, and returns the new balance. Use this when the user explicitly asks to buy or top up Fermi credits. Returns credits_purchased, new_balance and payment_status. If no card is saved yet, nothing is charged: it returns...

Parameters* required

api_keyvalue

Your Fermi API key. Omit it if your connector is signed in with permission to buy credits.

credits*integer

How many credits to buy, at least 1. Each is charged at the price in this tool's cost line.

check_account_and_creditsReports who you are to Fermi and what you can spend: whether you are using Fermi without an account or with one, your credit balance or free estimates left today, and what each tier costs. Use this before a paid estimate to check the price or balance, after one to see what is...1 params

Reports who you are to Fermi and what you can spend: whether you are using Fermi without an account or with one, your credit balance or free estimates left today, and what each tier costs. Use this before a paid estimate to check the price or balance, after one to see what is...

Parameters* required

api_keyvalue

Your Fermi API key. Omit it to ask about your connector's signed-in account, or about your free allowance without an account.

Readme

Details

Repository: github.com/kromatic-innovation/fermi
Transport: HTTP
Registry: MCP registry, active
Resources: 2
Prompts: 1
Tools verified: Nov 6, 2026