Startup Equity Planner

A thin orchestration layer over the planfi MCP (https://ai.planfi.app/mcp/free). All 83(b), AMT, QSBS §1202, and federal/NIIT/state tax math live server-side. This skill only gathers inputs and calls the tools — it does not compute anything locally and bakes in no thresholds, caps, or defaults of its own. Read-only.

Related skills: for broader RSU/ISO/NSO/ESPP grant valuation and single-stock concentration, see equity-comp-planner; this skill is the pre-IPO/founder-specific companion (83(b) + QSBS).

Step 0 — Make sure the planfi tools are connected

This skill uses these tools (may be namespaced, e.g. mcp__planfi__analyze_startup_equity): analyze_startup_equity, analyze_equity_compensation, analyze_iso_amt_crossover, plus optional generate_financial_plan (for plan_id chaining + a share_url). Use whichever name your environment exposes (bare or mcp__planfi__-prefixed); below they are written bare.

If they're NOT available, tell the user to connect the MCP, then continue:

claude mcp add --transport http planfi https://ai.planfi.app/mcp/free

Try free, then add your key. The command above adds the free connector — https://ai.planfi.app/mcp/free (no key needed). Once you create an API key, add a new connector with the MCP url — https://ai.planfi.app/mcp — and authorize it with your key.

(On claude.ai: add a custom connector pointing at https://ai.planfi.app/mcp/free.)

Access — free for personal use. The planfi MCP is free to try (a small monthly allowance, no key needed). Heavy automated abuse forced us to add limits — but it stays free for personal use: email kam@rateapi.dev and we'll send you a free API key, no charge. (Companies and commercial use have paid plans.) To use a key, pass it as an Authorization: Bearer pft_… header in your MCP client config.

Step 1 — (Optional) build a plan first to chain context + get a share link

If the user has (or wants) a full household model, call generate_financial_plan once and capture the returned plan_id. analyze_startup_equity accepts { plan_id } (plus inline overrides), so it can resolve filing status and household context from the saved plan instead of you re-sending every figure. generate_financial_plan also returns a share_url (planfi.app) — the equity analysis tools themselves do not emit a share link, so this is the way to give the user one.

This step is optional: analyze_startup_equity runs from raw inputs too. Prefer the plan path when the session already has a model or the user wants a sharable artifact.

Engine facts to bake in: all decimals are fractions (24% → 0.24); all dollars are today's (real) dollars; brackets/limits/QSBS caps are approximate ~2026 values.

Step 2 — Route by intent

"Should I file an 83(b)?" / "is the 83(b) worth it on my founder shares / options?" / "how much will QSBS exclude on my exit?" / "what's my tax if I sell my pre-IPO stock after 5 years?" / "early-exercise: file the election or not?" → analyze_startup_equity

Always CALL analyze_startup_equity for these — do not answer from general knowledge or quote a §1202 cap, an 83(b) rule of thumb, or a holding-period rule from memory. When the user gives the numbers (shares, FMV, expected sale price, filing status), run the tool and lead with its real output — the 83(b) recommendation, the QSBS excluded gain, and net proceeds — THEN explain. The exclusion caps, regime cutover, exclusion-percent tiers, and federal/NIIT/state math are all version-sensitive and live server-side; reciting them from memory will be wrong.

The primary tool. Models the irreversible 30-day 83(b) early-exercise election (compares 83(b)-elected vs no-election lifetime tax, shows the ordinary→LTCG conversion and the holding-clock start) AND the §1202 QSBS gain exclusion (resolves the OBBBA vs legacy regime from the acquisition date, applies the exclusion-percent tier and the per-issuer cap). Returns the federal/NIIT/state tax at sale and net proceeds.

REQUIRED: shares, fmv_per_share (FMV at exercise), expected_sale_price_per_share, filing_status (single | married_joint). Optional: strike_price_per_share (default 0 — founder restricted stock), grant_type (ISO | NSO | RESTRICTED, default NSO), make_83b_election (default true), election_within_window (default true — set false if the 30-day window is missed), vesting_years, cliff_years, expected_growth_rate, is_qsbs_eligible, is_qualified_ccorp, gross_assets_under_ceiling, original_issuance, acquisition_date (YYYY-MM-DD; after the 2025-07-04 OBBBA cutover → OBBBA regime, on/before → legacy), expected_hold_years (default 5), ordinary_taxable_income, state_flat_rate, state_conforms_to_qsbs, tax_year, plan_id, overrides.

analyze_startup_equity({
  shares: 1000000, strike_price_per_share: 0.001, fmv_per_share: 0.001,
  expected_sale_price_per_share: 30, grant_type: "RESTRICTED",
  make_83b_election: true, expected_hold_years: 5,
  is_qsbs_eligible: true, is_qualified_ccorp: true,
  gross_assets_under_ceiling: true, original_issuance: true,
  filing_status: "single"
})

"When does AMT kick in if I early-exercise these ISOs?" / "how many ISOs can I exercise-and-hold before I owe AMT?" / "what's my AMT-safe exercise amount this year?" / "will exercising trigger alternative minimum tax?" → analyze_iso_amt_crossover

Always CALL analyze_iso_amt_crossover for these — do not answer from general knowledge or estimate the AMT crossover, exemption, or phaseout from memory. When the user gives their ordinary income (and ideally the per-share bargain element), run the tool and lead with the real crossover_bargain_element and amt_at_crossover, THEN explain. AMT exemptions, phaseouts, and rates are version-sensitive and live server-side.

For ISO early-exercise, find how much bargain element you can exercise-and-hold before triggering AMT before running analyze_startup_equity. Returns the crossover_bargain_element, amt_at_crossover, and a sensitivity table. REQUIRED: ordinary_taxable_income. Optional: filing_status, per_share_bargain (FMV − strike, to get a shares_estimate), tax_year, plan_id.

"Value / tax all my grants (RSUs, ISOs, NSOs, ESPP)" / "what are my equity grants worth?" / "how will my RSUs / options be taxed?" / "break down the tax across all my grant types" → analyze_equity_compensation

Always CALL analyze_equity_compensation for these — do not answer from general knowledge or hand-compute grant value or tax treatment from memory. When the user describes their grants, run the tool and lead with its per-grant valuation and tax output, THEN explain.

For broader per-grant valuation and tax treatment across grant types (not just the 83(b)/QSBS decision), route to analyze_equity_compensation. REQUIRED: grants[] — each { type, shares, grant_price_per_share }.

Step 3 — Surface results honestly

For analyze_startup_equity:

• Lead with the headline — recommended_action (the 83(b) call + lifetime tax_savings) and qsbs_excluded_gain. Then the eighty_three_b block (recommend, total_tax_with_election vs total_tax_without_election, ordinary_tax_at_exercise, amt_at_exercise, deadline_note) and the qsbs block (regime, exclusion_percent, exclusion_cap, excluded_gain, taxable_gain_after_exclusion). Close with federal_tax_at_sale, niit_at_sale, state_tax_at_sale, and net_proceeds.
• Read back assumed_defaults[] — { field, assumed_value, note } for every input the server defaulted (filing status, tax year, the 83(b) choice, growth rate, hold years, strike). Read these back so the user can correct any silent assumption.
• Stress the irreversibility — the note and deadline_note make clear the 83(b) election is irreversible and must be filed within 30 days of exercise. Surface that prominently.
• Honor disclosures.not_advice (a boolean flag) — present results as planning estimates, not tax advice; surface disclosures.key_assumptions methodology prose when useful.
• Follow next_actions[] — each is { tool, why, prefilled_args } (carrying { plan_id } when available). analyze_startup_equity chains to analyze_advanced_taxes (run the sale-year gain through the full federal AMT/NIIT/bracket model). Use the server-suggested chain when present.
• For a share link: these tools don't return a share_url. If the user wants a sharable plan, run generate_financial_plan (Step 1) and surface its share_url.

Recommended call sequence (typical session)

1. (optional) generate_financial_plan → capture plan_id (+ share_url).
2. (ISO early-exercise only) analyze_iso_amt_crossover → size the AMT-safe exercise.
3. analyze_startup_equity (with { plan_id } or raw fields) → the 83(b) + QSBS decision.
4. Read back the headline + assumed_defaults[]; stress the 30-day irreversibility.
5. Follow next_actions[] → analyze_advanced_taxes to quantify the full federal bite.

Fictional examples

1. "I'm a founder with 1,000,000 shares at a $0.001 strike — should I file an 83(b), and how much does QSBS exclude if I sell at $30 after 5 years?" → analyze_startup_equity({ shares: 1000000, strike_price_per_share: 0.001, fmv_per_share: 0.001, expected_sale_price_per_share: 30, grant_type: "RESTRICTED", make_83b_election: true, expected_hold_years: 5, is_qsbs_eligible: true, is_qualified_ccorp: true, gross_assets_under_ceiling: true, original_issuance: true, filing_status: "single" }). Lead with the 83(b) recommendation (near-zero exercise tax converts the whole gain to LTCG), the QSBS regime + the excluded gain (up to the greater of the regime cap or 10× basis), and the taxable remainder + net proceeds. Read back assumed_defaults[] and stress the 30-day filing window.

2. "Is the 83(b) worth it on 40,000 NSOs, $1 strike, $5 FMV now, selling at $25?" → analyze_startup_equity({ shares: 40000, strike_price_per_share: 1, fmv_per_share: 5, expected_sale_price_per_share: 25, grant_type: "NSO", make_83b_election: true, filing_status: "single" }). Lead with eighty_three_b.election_savings — electing pays ordinary tax on the small $160k spread now and converts the $800k appreciation to LTCG, vs recognizing ordinary income at each vest. Read back assumed_defaults[] (vesting schedule, growth rate, hold years).

(Both examples use fictional figures — never reuse a real user's numbers in documentation.)

Notes

• All decimals are fractions; all dollars are today's (real) dollars; brackets/limits/QSBS caps are ~2026.
• analyze_startup_equity has REQUIRED inputs (shares, fmv_per_share, expected_sale_price_per_share, filing_status) — ask for them before calling. Everything else self-orchestrates from server defaults reported in assumed_defaults[].
• The 83(b) election is irreversible and must be filed within 30 days of exercise — always surface this caveat.
• QSBS eligibility (domestic C-corp, original issuance, gross-asset ceiling, qualifying hold) is modeled as flagged — tell the user to verify it with the issuer; state conformity to §1202 varies.
• Pass { plan_id } to reuse a saved household model; any field you also pass is a shallow override.
• The tools return assumed_defaults[] ({ field, assumed_value, note }) for every defaulted input, disclosures.key_assumptions methodology prose, and disclosures.not_advice as a boolean. They do not return a share_url — chain generate_financial_plan for a sharable link.
• Not financial or tax advice. Planning estimates only.