SAFE & Cap Table Calculator

SAFE ownership snapshot

safe_ownership

Read-onlyIdempotent

Calculate implied ownership and dilution for post-money SAFEs, resolve MFN, and estimate shares before a priced round.

Instructions

Implied ownership of post-money SAFEs (amount / post-money cap), combined SAFE dilution, MFN resolution, and optional share estimates. Use before a priced round.

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": {
      "safes": "<safes>"
    },
    "name": "safe_ownership"
  }
}

Input Schema

Name	Required	Description	Default
`safes`	Yes
`preSafeShares`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.1Oct 15, 2026

TDQS

B3.4/5.0

Behavior3/5

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

Annotations already declare readOnlyHint, idempotentHint and a closed-world scope, so the safety profile is covered. The description adds that MFN clauses get resolved and dilution is combined, but it omits the key behavioral caveat that the schema accepts pre-money SAFEs while the text only describes post-money math, and it says nothing about assumptions or output shape.

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?

Two dense sentences with the output scope front-loaded and the usage cue trailing. No filler, and the parenthetical '(amount / post-money cap)' efficiently conveys the ownership formula without a paragraph.

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

Completeness3/5

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

A read-only, idempotent analysis tool with no output schema, so the description's enumeration of computed results is useful, but an agent still lacks the return structure, the treatment of pre-money SAFEs, and how preSafeShares affects the result. Adequate but with clear gaps for a financial modeling tool.

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

Parameters3/5

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

Schema description coverage is 0% (only the discount fraction is annotated), so the description carries the burden. It partially compensates by naming domain concepts that map to parameters — amount, post-money cap (valuationCap), MFN (mfn flag) — but never explains preSafeShares or the pre-money/post-money type enum.

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

Purpose4/5

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

States specific computed outputs (implied ownership, combined SAFE dilution, MFN resolution, share estimates) rather than a generic verb, so an agent knows what the tool produces. It is distinguishable from model_priced_round via the 'before a priced round' cue, though no sibling is named outright.

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

Usage Guidelines3/5

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

'Use before a priced round' gives a timing trigger, which implies this is a pre-round analysis step rather than the round modeler itself. However, it never names the alternatives (model_priced_round, model_round_sequence) or states when this tool should not be used, leaving routing 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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