The proj.fi connector lets Claude, or any assistant that supports the Model Context Protocol (MCP), work on your proj.fi projects. Your assistant can read your models, run proj.fi's engine on them, draft memos and, if you allow it, propose input changes that you review in proj.fi.
Connector address:
https://www.proj.fi/api/mcpproj.fi is a project-finance modelling platform for solar and battery storage projects. proj.fi results are model outputs for analysis. They are not investment, tax, legal or accounting advice.
What it does
- Reads your projects. Inputs with labels, units and sources; saved versions; headline results.
- Calculates with proj.fi's engine. Returns, DSCR, debt sizing, tax equity, sensitivities, scenarios, goal seek, downside cases and refinancing. Every number comes from the same deterministic engine as the proj.fi app, so the assistant quotes numbers rather than computing them.
- Runs what-ifs without saving them. Most calculation tools accept what-if values for editable inputs, used for that one calculation. They are never saved.
- Writes deliverables. IC memo, lender memo, one-pager, sources and uses, charts, and the full Excel model as a download link.
- Maps documents you give your assistant to proj.fi inputs. Give your assistant the text of a PPA or term sheet; it maps the terms to proj.fi inputs, with units, and proposes them for your review. proj.fi has no document reader of its own on this connector and stores no document text.
- Proposes input changes for your review (only with Read and propose changes). Proposals wait as a review in your Working model and change nothing until you accept them in proj.fi.
Who can use it
You need a proj.fi account. proj.fi opens to teams by approval, and every account has an accepted NDA. If you don't have one, start connecting anyway: the sign-in page has Request access. We email you when your access is ready; then connect again from your assistant. You can also request access here.
The connector sees exactly what you can see in proj.fi, in your own organization.
Set up in Claude
- In Claude, open Settings → Connectors and choose Add custom connector. Custom connectors are available on Claude's Free, Pro, Max, Ultra, Team and Enterprise plans; on Team and Enterprise plans an Owner adds the connector for the organization first, and members then connect to it individually.
- Name it proj.fi and paste
https://www.proj.fi/api/mcp. - Choose Connect. A proj.fi window opens.
- Sign in with your proj.fi account. If your account uses two-step sign-in, enter your authenticator code. If you haven't accepted the NDA, you accept it here.
- Choose what Claude may do:
- Read projects: see inputs and results, trace how a number is calculated, compare versions, and run calculations.
- Read and propose changes: also suggest input changes, which wait as a review in your Working model, and create inputs links that open in proj.fi.
- Choose Allow. You return to Claude.
The same steps work on claude.ai, Claude Desktop and Claude in Excel.
Claude Code: run
claude mcp add --transport http projfi https://www.proj.fi/api/mcpthen sign in when Claude Code opens the browser. Because Claude Code receives the sign-in on your own computer, proj.fi's consent page warns that any program on the computer could be listening. Continue only if you just started the connection yourself.
Other assistants: proj.fi sends sign-ins only to Claude and to apps on your own computer. Other destinations are refused at the consent page.
You can also find the address and these steps in proj.fi under Settings → Connected apps.
The tools
A Read and propose changes connection has 44 tools. A Read projects connection has 42: everything below except Propose input changes for review and Inputs link for proj.fi.
| Group | Tools | What they do |
|---|---|---|
| Projects and versions | List proj.fi projects · List saved versions · Read project inputs · Read project results · Trace a result · Compare versions | Find a project, read its inputs or a saved version, calculate headline results, show how one result is built, compare two versions |
| Review | Propose input changes for review · Inputs link for proj.fi | Stage input changes as a review in your Working model; turn a model into a link that opens in proj.fi's Import inputs |
| One-call workflows | Quick screen · Full evaluation · IC packet · Lender pitch · PPA screen · Portfolio rollup | Several analyses in one call; the rollup compares up to 25 of your organization's projects |
| Base case and checks | Base case · Check model · DSCR schedule · Explain returns · Explain DSCR | Full results, engine consistency checks, the quarterly debt schedule, plain-language explanations |
| Sensitivities and scenarios | Sensitivity tornado · Compare scenarios · Downside cases · Debt scenarios | Input swings, named scenarios side by side, the lender stress package |
| Solvers and debt | Goal seek · Breakeven · Maximum debt · Size tax equity · Debt sizing tests · Refinancing | Solve an input for a target, size debt and tax equity, refinancing at maturity |
| Structures and offers | Compare financing structures · Structure comparison table · Evaluate PPA offers · Tax credit transfer pricing | Financing presets, structure variants, PPA offers ranked, credit transfer prices |
| Deliverables | One-pager · IC memo · Lender memo · Sources and uses · Returns chart (SVG) · IC narrative · Excel model | Markdown memos and tables, an SVG chart, the full formula-rich Excel workbook |
| Calculators and reference | IRR of cash flows · NPV of cash flows · Compare two results · Default assumptions | Date-aware IRR and NPV, rank what changed between two results, proj.fi's default assumptions |
Deal documents are read by your assistant, not by proj.fi. Give it the text (a pricing clause, a term sheet) and ask it to map the terms to proj.fi inputs; the proposal it raises shows each value for you to check against the document.
Start a model that isn't in proj.fi yet
Every analysis tool, and Read project inputs, also takes an asset type (solar or bess) instead of a project. The model is the one proj.fi opens a new project with: proj.fi's standard values, financing off. Give your project's own values as what-ifs (the same field ids Read project inputs lists). Nothing is saved.
Results say which key facts are still at proj.fi's starting values (for solar: capacity, NTP and COD dates, P50 yield, PPA price and term, capex per watt, O&M). Until you give those, the results describe proj.fi's starting values, not your project.
To take the model into proj.fi, ask for an inputs link (needs a Read and propose changes connection). In proj.fi, open a new project of the same type, then open the link, or use Share inputs ▸ Import from link. proj.fi shows what will change and applies nothing until you choose Apply; any key fact you didn't give is still flagged for entry. Anyone with the link can load those inputs for 30 days. Revoke it in Share inputs ▸ Manage share links.
Permissions and safety
- Your permissions, nothing more. Every read runs as you, under the same database access rules as the app. A connected assistant cannot write to proj.fi's tables, cannot open files in storage, and cannot change project sharing, members or settings. With Read and propose changes it can create an inputs link that you own and can revoke under Share inputs ▸ Manage share links.
- Changes wait for you. A proposal is checked against the inputs the assistant read. If the project changed since, the proposal is refused. It then appears as a review in your Working model. Nothing changes until you open the review link in proj.fi and accept it. Your Base model is never written.
- What-ifs are never saved. What-if values apply to one calculation only.
- Only editable inputs. Proposals and what-ifs accept only inputs that Read project inputs marks
editable: true, with a value of the right type. - Calls are logged. Each tool call is written to your organization's audit log with you as the actor: the tool, the project, the outcome and the time taken. The arguments, values and results are not recorded.
- Revoke at any time. In proj.fi, open Settings → Connected apps and choose Revoke. Access ends at once: proj.fi checks the connection on every request. Removing proj.fi in Claude does not remove it in proj.fi; revoke it there too.
- No proj.fi AI spend. The connector's tools run on the deterministic engine. proj.fi makes no AI model call to answer them.
Limits
| Limit | Value |
|---|---|
| Requests per person | 60 per minute |
| Calculation tools | 30 per minute per person |
| Proposals | 10 per minute per person |
| Request size | 256 KB |
| Inputs changed per proposal | 100 |
| What-if values per call | 50 |
| Projects listed | 200 most recently updated |
| Portfolio rollup | 25 projects |
| Changed inputs shown by Compare versions | 100 |
| Excel download link | valid 1 hour; the file is removed after 24 hours (on that project's next export or upload) |
| Inputs link | 30 days, revocable in proj.fi |
Other limits:
- Projects shared in from another organization appear in your list marked as shared in. Open them in proj.fi; the connector opens your own organization's projects only.
- Excel exports are available for your own organization's projects.
- Proposals need Fi, proj.fi's in-app analyst, switched on for your organization.
- Two-step sign-in accounts confirm the connection again every 30 days, and whenever you add or remove an authenticator.
- Sessions end at proj.fi's maximum sign-in age, 7 days by default; reconnect when asked.
Troubleshooting
| What the assistant shows | Why | What to do |
|---|---|---|
| Sign in to proj.fi to use this connector. | No sign-in yet | Choose Connect in Claude and sign in. |
| Your proj.fi connection has ended. Reconnect proj.fi to continue. | The sign-in expired, reached its maximum age, or was ended | Reconnect from Settings → Connectors in Claude. |
| This connection was removed in proj.fi. Reconnect proj.fi to continue. | The connection was revoked in proj.fi, or you changed organization | Reconnect. If you revoked it on purpose, nothing to do. |
| Your proj.fi account uses two-step sign-in. Reconnect proj.fi and confirm with your authenticator app. | The connection was approved without two-step sign-in, or 30 days have passed | Reconnect and enter your authenticator code. |
| Your two-step sign-in changed, so this connection needs confirming again. | You added or removed an authenticator | Reconnect and confirm. |
| proj.fi needs a signed NDA on your account. Open proj.fi to sign it, then try again. | No NDA on file | Open proj.fi, accept the NDA, try again. |
| This isn't a proj.fi connection. Reconnect proj.fi from your assistant. | The token is not a proj.fi connector token | Remove and add the connector again. |
| proj.fi couldn't check your sign-in just now. Try again in a moment. | Sign-in service briefly unavailable | Wait a few seconds and retry. |
| Connecting assistants to proj.fi isn't switched on yet. | The connector is off on this deployment | Contact support@proj.fi. |
| proj.fi can't connect to this app. Only Claude and apps on this computer can be connected. | Consent page: the app asked to return somewhere proj.fi doesn't allow | Connect from Claude or a local app. |
| This sign-in request has expired or was already used. Start connecting again from your assistant. | Consent page opened twice or too late | Start again from Claude. |
| Confirm it's you with your authenticator app, then try again. | Consent page: two-step sign-in needed | Sign in with your authenticator code. |
| Your account isn't in an organization yet. | Account not yet set up | Contact support@proj.fi. |
| This connection can read projects but not propose changes. Reconnect proj.fi and allow proposals. | You chose Read projects | Revoke in proj.fi, reconnect, choose Read and propose changes. |
| Too many requests to proj.fi. Try again in N seconds. | A per-person limit was reached | Wait the stated time. |
| This project is shared with you from another organization. Open this one in proj.fi. | Shared-in project | Work on it in proj.fi. |
| You don't have access to that in proj.fi. | Not visible to you | Check the project id with List proj.fi projects. |
| That saved version isn't available. | Wrong or deleted version id | Use an id from List saved versions. |
| These can't be overridden / These inputs can be read but not changed through a proposal. | The input isn't editable | Use inputs marked editable: true, or change it in proj.fi. |
| … takes a number (or string, boolean). | Wrong value type | Send the right type. |
| One of these values is outside what proj.fi accepts for that input. | For example a negative price or capex | Correct the value. |
| The project changed since you read it. Read the inputs again, then propose. | Someone changed the Working model | Read inputs again, then propose with the new inputs_hash. |
| You can view this project but not propose changes to it. | Your role in proj.fi is view-only for this project | Ask an admin, or work read-only. |
| Fi reviews aren't switched on for your workspace. | Fi is off for your organization | Contact support@proj.fi. |
| Your workspace has reached its review limit for now. Try again later. | Fi's workspace limits reached | Try later. |
| Give either project_id or asset_type, not both. | A call named both a project and a new model, or neither | Name one. |
| A new model has no saved versions; leave version out. | A version was given with an asset type | Leave the version out. |
| This model couldn't be calculated. Open it in proj.fi to see what needs attention. | The model has an input the engine can't use | Open the project in proj.fi and fix it. |
| This model's dates or asset life are outside what proj.fi supports. | Asset life outside 1–100 years, or construction 30 years or more | Correct the dates in proj.fi. |
| Excel exports are available for your own organization's projects. | Shared-in project | Export it in proj.fi. |
| Those arguments don't fit. | A tool argument is missing or invalid; the message names it | The assistant should correct the argument. |
| … hit an unexpected error in proj.fi (reference xxxxxxxx). Nothing in your project was changed. | An unexpected failure, logged with that reference | Retry. If it repeats, email support@proj.fi with the reference. |
| proj.fi is unavailable right now. Try again in a minute. | proj.fi's database is unreachable | Retry shortly. |
Your data
- proj.fi records each connection (the app, the access you chose, when you approved it and last used it) and writes one audit entry per tool call to your organization's audit log, without arguments, values or results.
- Document text you give your assistant stays with your assistant. proj.fi receives only the values the assistant proposes, as a proposal you review.
- Proposals are stored as a review in your project. Excel files are stored in the project's private storage and removed after 24 hours.
- Your conversation and the results returned to your assistant are handled by your assistant's provider under your agreement with it.
Full details: proj.fi Privacy Policy, section 9.
Support
- Product and account help: support@proj.fi
- Security reports: security@proj.fi (also at /.well-known/security.txt)