startup-valuation

Marketplace Metrics

valuation_marketplace

Read-onlyIdempotent

Compute marketplace health and valuation metrics—take rate, GMV multiple, buyer retention, network density—by choosing a method and providing its required inputs.

Instructions

Marketplace health and valuation: take rate, GMV revenue-multiple valuation, buyer retention, and network density. Method selects the metric. Use for two-sided transaction marketplaces; for subscription software use valuation_saas. Parameters apply per method: take_rate needs revenue + gmv; gmv_multiple needs gmv + multiple; buyer_retention needs buyers_period_1 + buyers_repeat; network_density needs active_buyers + active_sellers + total_users. Only method is required; other parameters are method-dependent, so supply those named for the selected method and omit the rest (documented defaults apply where defined). Returns an object with value, method, inputs, assumptions, chapter, formula_number and calculation steps. Pure arithmetic: no I/O and no external calls, and numeric results are returned rounded to 2 decimals. No authentication, credentials, or rate limits apply. Supplying an unknown method, or leaving unset a parameter that the chosen method requires, returns an error instead of a value.

Input Schema

TableJSON Schema

Name	Required	Description
`gmv`	No	Gross merchandise value (total transaction volume), currency units.
`method`	Yes	Formula to apply. Options: take_rate = Take rate = revenue / GMV.; gmv_multiple = Valuation = GMV × multiple.; buyer_retention = Retention = repeat buyers / base-period buyers.; network_density = Density = active buyers × active sellers / total users.
`revenue`	No	Revenue for the period, currency units.
`multiple`	No	Exit or market multiple applied to the metric.
`total_users`	No	Total users (buyers + sellers) in the period.
`active_buyers`	No	Active buyers in the period.
`buyers_repeat`	No	Distinct buyers from the base period who purchased again.
`active_sellers`	No	Active sellers in the period.
`buyers_period_1`	No	Distinct buyers in the base period.

Output Schema

TableJSON Schema

Name	Required	Description
`error`	No	Error message when the call fails.
`steps`	No	Intermediate steps for traceability.
`value`	Yes	Computed valuation or metric.
`inputs`	No	Echo of the normalised inputs used.
`method`	No	Formula / method name that produced the result.
`chapter`	No	Source textbook chapter.
`assumptions`	No	Modelling assumptions applied.
`formula_number`	No	Source textbook formula number (e.g. '3.1').

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Sep 30, 2026

TDQS

A4.8/5.0

Behavior5/5

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description still adds substantive behavior: pure arithmetic with no I/O or external calls, results rounded to 2 decimals, no auth/credentials/rate limits, and explicit error semantics for unknown methods or missing required parameters.

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 purpose, then routing, then per-method parameter contracts, then return/behavior notes — a logical order with no filler. It is dense and somewhat long, and the return-field enumeration overlaps the output schema, but each sentence carries operational weight.

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?

For a 9-parameter, 4-method calculator with an output schema, the description covers selection, conditional inputs, error behavior, precision, and safety context. An agent has everything needed to choose a method and supply the correct arguments.

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 description coverage is 100%, so the baseline is 3, but the description adds genuinely new information the schema cannot express: the conditional dependency mapping each method to its required inputs (take_rate -> revenue+gmv, gmv_multiple -> gmv+multiple, etc.) and the rule that unneeded parameters should be omitted. It stops short of units or edge-case semantics, so not a 5.

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+resource (marketplace health and valuation metrics) and enumerates the four metrics computed. It explicitly names the sibling it is not (valuation_saas) and the domain it serves (two-sided transaction marketplaces), so an agent can separate it from the other 13 valuation_* tools without opening a schema.

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 an explicit when-to-use ('two-sided transaction marketplaces') and when-not ('for subscription software use valuation_saas'), plus the per-method parameter contract and the instruction to omit parameters not named for the selected method. Nothing about invocation is left to inference.

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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