409A Compliance MCP for AI. Structure grants legally. Avoid massive, unexpected tax penalties.
Works with every AI agent you already use
…and any MCP-compatible client








How this MCP server connects to your AI agent
US Section 409A Impact Calculator provides compliance checks for stock options. It helps you determine legal minimum strike prices, estimate tax penalties from non-compliant grants, and verify exercise window rules under US law.
What AI agents can do with US Section 409A Impact Calculator Automation
Lookup exercise rules
Provides specific regulatory information about option exercise windows and their tax consequences.
Analyze grant compliance
Runs a full audit of proposed grants, checking them against current law and option type rules (ISO/NSO).
Calculate minimum strike
Determines the lowest legally permissible strike price for an option grant.
It audits proposed option grants against current Fair Market Value (FMV) and option type rules.
It calculates the lowest legally permissible strike price for any given stock option grant.
It figures out the expected financial penalty if options are granted below FMV.
It shows the regulatory window and associated tax implications for employees exercising their rights.
Ask an AI about this
Waiting for input…
What AI agents can do with US Section 409A Impact Calculator (4 Tools)
These four tools let you check grant compliance, calculate minimum required strikes, model potential tax penalties, and review option exercise rules for US stock options.
Make your AI actually useful.
Add this MCP to Claude, Cursor, or Windsurf and your AI stops guessing. It gets real tools to look things up, take action, and handle the stuff you keep doing by hand.
Start using US Section 409A Impact Calculator on VinkiusLookup Exercise Rules
Provides specific regulatory information about option exercise windows and their tax consequences.
Analyze Grant Compliance
Runs a full audit of proposed grants, checking them against current law and option...
Calculate Minimum Strike
Determines the lowest legally permissible strike price for an option grant.
Estimate Tax Penalty
Calculates a financial estimate of the tax burden if options are granted below FMV.
Security and governance baked right in.
Pick your AI client below to get set up. Just create a Vinkius account, subscribe, and you're instantly up and running. We handle the entire backend infrastructure, delivering out-of-the-box support for HTTPS Streamable, SSE, and OAuth2—zero messy routing required.
Choose How to Get Started
Build a custom MCP for your own tools, or connect a ready-made integration from our catalog.
Build Your Own
Turn any API into an MCP. Import a spec, define Agent Skills, or deploy with MCPFusion.
- Import from OpenAPI, Swagger, or YAML specs
- Create Agent Skills with progressive disclosure
- Deploy to edge with MCPFusion framework
- Built in DLP, auth, and compliance on every call
- Real time usage dashboard and cost metering
- Publish to catalog or keep private
Make Your AI Do More
Start with US Section 409A Impact Calculator, then connect any of our 5,100+ other servers whenever your AI needs more. One click, no limits.
- Use this MCP plus 5,100+ others, all in one place
- Add new capabilities to your AI anytime you want
- Every connection is secured and compliant automatically
- Track usage and costs across all your servers
- Works with Claude, ChatGPT, Cursor, and more
- New servers added to the catalog every week
Independent Platform Disclaimer: Vinkius is an independent platform and is not affiliated with, endorsed by, sponsored by, verified by, or otherwise authorized by US 409A Impact Calculator. All third-party trademarks, logos, and brand names are the property of their respective owners. Their use on this website is strictly for informational purposes to identify service compatibility and interoperability.
VINKIUS INFRASTRUCTURE
Cloud Hosted
Managed infra
V8 Isolated
Sandboxed per request
Zero-Trust Proxy
No stored credentials
DLP Enforced
Policy on every call
GDPR Compliant
EU data residency
Token Compression
~60% cost reduction
Built on the Model Context Protocol (MCP) for Claude, ChatGPT, Cursor, and more
The Model Context Protocol standardizes how applications expose capabilities to LLMs. Instead of operating in isolation, your AI gains direct access to external platforms, live data, and real-world actions through secure, standardized connections.
This connection provides 4 powerful capabilities that interface natively with Claude, ChatGPT, Cursor, and other compatible AI platforms. No middleware. No custom integration required.
The headache of checking option compliance manually, Solved with Vinkius AI Gateway
Today, structuring equity grants means juggling multiple spreadsheets. You're cross-referencing current FMV against proposed strike prices, and then having to check whether the grant is compliant based on if it’s an ISO or NSO. It takes hours of manual checking, and one small formula error can create a massive tax headache for your company.
With this MCP, you simply ask your agent to run an audit. You input the parameters, and the tool immediately confirms compliance status—you get a single, clear pass/fail report that tells you exactly what needs adjusting.
Analyze grant compliance with `analyze_grant_compliance`
You don't have to manually check the strike price against FMV, and then separately verify if it meets ISO or NSO requirements. The tool handles all of that in one function call.
Now you get a unified compliance report. You know instantly where the risk lies—whether it’s the strike price, the option type, or the overall structure.
What your AI can actually do with this
This MCP handles the complicated math behind employee stock option compliance. If your company is issuing grants, understanding Section 409A isn't optional—it’s necessary to avoid massive unforeseen tax liabilities. Your agent can use this MCP to immediately determine if a proposed grant structure meets legal standards by running an audit with analyze_grant_compliance.
It calculates the absolute lowest strike price allowed using calculate_minimum_strike, and it estimates the financial penalty you'd face if those rules are broken, thanks to estimate_tax_penalty. Furthermore, it provides clear guidance on tax implications and regulatory windows via lookup_exercise_rules. When your team needs this level of financial precision, Vinkius makes sure these critical tools are available right where you need them.
019ed0ff-e7e6-71f7-a2cc-d9dd738fc262 Here's how it actually works
The bottom line is you stop guessing about complex tax law and start working with verifiable numbers.
Input key variables like current Fair Market Value (FMV) and proposed strike price into your agent.
The MCP runs calculations against current IRS guidelines to check compliance, calculate minimum strikes, or model tax penalties.
You get a clear report detailing the legality of the grant, the exact penalty amount, and any necessary adjustments.
Who is this actually for?
This MCP is for finance professionals, corporate legal counsel, and HR leaders who deal with equity compensation. If you're tired of spending days cross-referencing IRS guidelines or using outdated spreadsheets to structure a single grant, this is for you.
Uses the MCP to audit potential grants and ensure that new stock option structures adhere strictly to 409A law.
Runs simulations using estimate_tax_penalty before finalizing any compensation plan, protecting the company from unexpected tax bills.
Consults compliance checks to make sure new employee grant packages are structured correctly on day one.
What Changes When You Connect
Eliminate compliance risk before the grant goes out. Use analyze_grant_compliance to get an instant audit on any proposed option package.
Stop overpaying or under-structuring options. The MCP uses calculate_minimum_strike to give you the exact, lowest legal strike price floor.
Predict tax penalties instantly. Never guess about non-compliant grants again; just run a check with estimate_tax_penalty and see the actual financial hit.
Simplify complex rules. Need to know when employees can exercise? Use lookup_exercise_rules for clear, actionable guidance on regulatory windows.
Save hours of manual review. Instead of cross-referencing multiple IRS documents, your agent handles the entire compliance check in one go.
See it in action
Structuring a New Employee Grant
The HR Director needs to offer a senior engineer an option package. They ask their agent to run analyze_grant_compliance against the proposed strike price and FMV, instantly confirming that the grant is compliant for both ISO and NSO types.
Reviewing Past Grants
The VP of Finance wants to know what happens if they accidentally granted options below market value. They use estimate_tax_penalty to model the worst-case scenario, allowing them to correct processes before a problem hits.
Setting Founder Incentives
The CEO needs a legal minimum strike price for early hires. Using calculate_minimum_strike, they get the precise floor needed to ensure all future grants are legally structured and defensible.
The honest tradeoffs
Relying on generalized tax calculators
Using an online calculator that only addresses basic strike price rules but ignores option type (ISO vs NSO) or current FMV requirements.
You must run analyze_grant_compliance because it checks the grant against all required parameters, including both ISO/NSO types and current market values.
Ignoring exercise deadlines
Assuming that an employee can use their options whenever they want without checking tax rules.
Always verify the timeline using lookup_exercise_rules to understand when tax implications kick in and what windows apply.
Manual calculation of penalties
Trying to calculate a penalty spread by hand, which is prone to formula errors and misses interest accrual.
Use estimate_tax_penalty to get the precise financial liability, including all applicable interest and tax rates.
When It Fits, When It Doesn't
Use this MCP if your primary concern is compliance risk: Are these stock options legal? What is the minimum permissible strike price? If you need to model potential financial liabilities from improper grants or verify complex timing rules, this is your toolset. Don't use it if you are trying to analyze general market trends, perform valuation models for non-equity assets, or manage payroll—those require different tools entirely.
Questions you might have
How do I check if my proposed grant is legal using analyze_grant_compliance? +
You must provide the current FMV and the proposed strike price. The analyze_grant_compliance tool will then audit the proposal against both ISO and NSO requirements, telling you if it's compliant.
What is the minimum legal strike price? Use calculate_minimum_strike. +
The calculate_minimum_strike function determines the absolute lowest price legally allowed. You just need to feed it the current Fair Market Value (FMV) for that calculation.
How do I estimate tax penalties with estimate_tax_penalty? +
You run estimate_tax_penalty by specifying the grant's strike price and the actual FMV. The tool then calculates the exact taxable spread and expected penalty amount.
What does lookup_exercise_rules tell me about tax implications? +
lookup_exercise_rules gives you specific details on when options can be exercised and what that means for taxes. It's essential for advising employees on timing.
How does `analyze_grant_compliance` account for different option types like NSO versus ISO? +
It evaluates compliance by factoring in whether the grant qualifies as an Incentive Stock Option (ISO) or Non-Qualified Stock Option (NSO). The tool uses the specific type and current FMV to give a definitive pass/fail assessment against IRS guidelines.
If I provide incorrect data, what should I expect from `calculate_minimum_strike`? +
The function requires an accurate Fair Market Value (FMV) for the strike price calculation. If you input invalid or contradictory financial data, it returns a specific validation error detailing which piece of market information needs correction.
To get the full picture, how should I sequence `analyze_grant_compliance` and `estimate_tax_penalty`? +
First, use analyze_grant_compliance to confirm basic legal eligibility. Next, you run estimate_tax_penalty using the grant details to calculate the actual financial risk associated with any non-compliant elements.
Are there rate limits when calling `lookup_exercise_rules` repeatedly for different scenarios? +
Vinkius manages usage, and repeated calls to lookup_exercise_rules are allowed within standard API thresholds. If your workflow requires high-volume testing, check the Vinkius dashboard for specific rate limit details.
How can I find the minimum strike price for a new grant? +
Use the calculate_minimum_strike tool by providing the current Fair Market Value (FMV) and the valuation date.
What happens if I grant options below the FMV? +
Granting below FMV triggers a 20% federal penalty tax plus interest. You can use estimate_tax_penalty to calculate the projected financial impact.
Does this tool cover ISO and NSO differences? +
Yes. The lookup_exercise_rules tool provides specific exercise windows and tax summaries for both ISO and NSO types.
We've already built the connector for 409A Compliance. Just plug in your AI agents and start using Vinkius.
No hosting. No infrastructure. No complex setup.
All 4 tools are live and waiting.
You're up and running in seconds.
Vinkius gives your AI agents access to the full catalog of app connectors, all fully managed, secure, and enterprise-ready. One subscription, every tool you need.
Built, hosted, and secured by Vinkius. You just connect and go.