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Turn distribution parameters into a min–max range

convert_distribution_to_range
Read-onlyIdempotent

Turns a distribution's parameters into the low and high ends of the range that holds a chosen share of outcomes, by default the middle 90%. It also gives the mean, median, mode, standard deviation and any percentiles you ask for. If you give a threshold, it gives the chance of landing below and above it. Use this when you have distribution parameters, from a model or from fermi (a companion forecasting server from Kromatic, the company behind Neumann, whose estimates carry next_steps.simulate.root_node), and want to know what they mean in plain numbers. Its reverse is convert_range_to_distribution, and the range it returns can be passed straight back to it. Values that do not apply, such as a uniform distribution's mode, come back as null with a note explaining why. Cost: free; uses no credits and no free runs.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "distribution_type": "<distribution_type>",
      "distribution_params": "<distribution_params>"
    },
    "name": "convert_distribution_to_range"
  }
}

Input Schema

NameRequiredDescriptionDefault
quantilesNoA list of percentiles to report. Each is a fraction from 0 to 1: 0.05 is the 5th percentile, the value 5% of outcomes fall below. No repeats. Default [0.05, 0.1, 0.5, 0.9, 0.95], returned under keys p5, p10, p50, p90 and p95.
thresholdNoOptional value to compare against. The result gives the chance of being at or below it and the chance of being above it. For whole-number distributions it gives the chance of being below and above it, and notes the chance of landing exactly on it.
percentile_rangeNoA single fraction: the share of outcomes the returned range should hold, centred on the median. The default 0.9 means the middle 90%, so the range runs from the 5th to the 95th percentile.
distribution_typeYesThe distribution's name. Accepts every type a model input accepts: normal, log_normal, uniform, triangle, beta (values are fractions from 0 to 1), gamma, exponential, poisson, bernoulli, binomial, categorical, constant, discrete_normal, discrete_lognormal and discrete_gamma. categorical returns no range. dirichlet, multivariate_normal and constant_array produce lists of values, so every number comes back null. This is wider than convert_range_to_distribution, which cannot fit poisson or categorical.
distribution_paramsYesThe distribution's parameters, in the same form a model input uses, for example {"mean": 100, "std": 15} for normal or {"mu": 9.2, "sigma": 0.6} for log_normal.

Output Schema

NameRequiredDescriptionDefault
stdYes
meanYes
modeYes
notesNoExplanations, for example why a value is null, or the chance of landing exactly on the threshold for whole-number distributions.
medianYes
billingNoWho you are and what this call cost: principal, auth source, credits debited and balance, or the anonymous allowance left today.
supportYes
intervalYesThe range holding the chosen share of outcomes, in the input shape convert_range_to_distribution accepts. Null where a range does not apply.
quantilesYesRequested percentiles, keyed p5, p50 and so on.
thresholdYesChances of landing below and above the threshold. Null when no threshold was given.
distribution_typeYes
distribution_paramsYes

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed8 schema fields changed
    • removedInput schema / properties / api_key
      Removed value: -{
      -  "anyOf": [
      -    {
      -      "type": "string"
      -    },
      -    {
      -      "type": "null"
      -    }
      -  ],
      -  "default": null,
      -  "description": "Your Neumann API key. Optional: this tool is free either way. Pass it so the billing block in the result shows your account. Get one by creating an account (POST https://neumann.kromatic.com/api/v1/accounts, which returns the key once); setup docs: https://kromatic.com/mcp/neumann.",
      -  "title": "Api Key"
      -}
    • changedOutput schema / $defs / BillingInfo / properties / auth_source / description
      Previous value: -"How you were identified: bearer (a signed-in connection token), api_key (the api_key argument) or anonymous."New value: +"How you were identified: bearer (a credential sent in the Authorization: Bearer header) or anonymous."
    • changedOutput schema / $defs / BillingInfo / properties / auth_source / enum
      Previous value: -[
      -  "bearer",
      -  "api_key",
      -  "anonymous"
      -]New value: +[
      +  "bearer",
      +  "anonymous"
      +]
    • changedOutput schema / $defs / BillingInfo / properties / charged_to / enum
      Previous value: -[
      -  "anonymous_allowance",
      -  "credits",
      -  "none"
      -]New value: +[
      +  "anonymous_allowance",
      +  "free_daily_run",
      +  "credits",
      +  "none"
      +]
    • addedOutput schema / $defs / BillingInfo / properties / free_run_limits
      Added value: +{
      +  "anyOf": [
      +    {
      +      "$ref": "#/$defs/SignedInLimits"
      +    },
      +    {
      +      "type": "null"
      +    }
      +  ],
      +  "default": null,
      +  "description": "The free signed-in tier's bounds. Null unless the account signed in with Kromatic."
      +}
    • addedOutput schema / $defs / BillingInfo / properties / free_runs_remaining_today
      Added value: +{
      +  "anyOf": [
      +    {
      +      "type": "integer"
      +    },
      +    {
      +      "type": "null"
      +    }
      +  ],
      +  "default": null,
      +  "description": "Free signed-in runs left in the current UTC day, counting this call. Null unless the account signed in with Kromatic.",
      +  "title": "Free Runs Remaining Today"
      +}
    • addedOutput schema / $defs / BillingInfo / properties / free_runs_reset_at
      Added value: +{
      +  "anyOf": [
      +    {
      +      "type": "string"
      +    },
      +    {
      +      "type": "null"
      +    }
      +  ],
      +  "default": null,
      +  "description": "ISO-8601 instant the free signed-in runs next refill (the next UTC midnight). Null unless the account signed in with Kromatic.",
      +  "title": "Free Runs Reset At"
      +}
    • addedOutput schema / $defs / SignedInLimits
      Added value: +{
      +  "description": "The free signed-in tier's bounds (neumann#334), rendered from ``Settings``.",
      +  "properties": {
      +    "max_nodes": {
      +      "description": "Maximum nodes in a free run's graph.",
      +      "title": "Max Nodes",
      +      "type": "integer"
      +    },
      +    "max_trials": {
      +      "description": "Maximum trials in a free run.",
      +      "title": "Max Trials",
      +      "type": "integer"
      +    },
      +    "runs_per_day": {
      +      "description": "Free runs per UTC calendar day.",
      +      "title": "Runs Per Day",
      +      "type": "integer"
      +    }
      +  },
      +  "required": [
      +    "runs_per_day",
      +    "max_trials",
      +    "max_nodes"
      +  ],
      +  "title": "SignedInLimits",
      +  "type": "object"
      +}
  2. Added

TDQS

A4.8/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Beyond the annotations (readOnly/idempotent/non-destructive), it discloses null-with-explanation behavior for inapplicable values, threshold semantics (below/above probabilities), the round-trip compatibility with the reverse tool, and the cost profile ('free; uses no credits and no free runs') — all things the annotations do not convey.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the core behavior and default (middle 90%), then alternatives and edge cases. The parenthetical about Kromatic/Neumann and next_steps.simulate.root_node is tangential trivia that slows scanning, but every other sentence earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With an output schema present and full annotation coverage, the description supplies exactly the missing layer: null-handling, threshold behavior, the inverse relationship, and cost. Nothing an agent needs to call this correctly is absent.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3, but the description adds real meaning: that params come in 'the same form a model input uses' (with fermi as an external source) and that the returned range can be fed straight back to the reverse tool. It still defers percentile and threshold detail to the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('turns a distribution's parameters into the low and high ends of the range') and explicitly names its sibling and inverse, convert_range_to_distribution, so an agent can separate the two without opening schemas.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives a concrete when-to-use condition ('when you have distribution parameters ... and want to know what they mean in plain numbers'), names the source of such parameters (a model or fermi), and explicitly routes the opposite direction to convert_range_to_distribution.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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