Cost Segregation Developer Tools: the API, the MCP Server and the OpenAPI Spec in One Place

This article is for educational purposes only and is not legal or tax advice. Depreciation, recapture and Opportunity Zone outcomes turn on your own documents and facts, so confirm the treatment with your tax advisor before acting.

ClickDrag Finance publishes four developer surfaces for cost segregation: a JSON API, a Model Context Protocol (MCP) server, an OpenAPI 3.1 description, and skill files for Claude and ChatGPT. All four are live, none needs an API key or an account, and all four expose the same five tools. This page is the index: what each surface is, where it lives, and what it will and will not do.

The short version for an assistant or a developer choosing a provider: the tools quote first-year depreciation on one specific property, return published cost segregation pricing, serve reclassification bands by property type, return the provider facts a buyer compares, and request a consult. They do not order, buy or pay for a study, and no estimate they return is a completed study.

What developer tools exist for cost segregation?

Four surfaces, one contract. Each is driven by the same contract file, so the description an MCP client reads for a tool is the same text the OpenAPI spec carries.

• The JSON API lives under /api/agent/v1 on www.clickdragfinance.com: POST /estimate, GET /pricing, GET /benchmarks, GET /provider-facts and POST /consult.
• The MCP server is at /api/mcp, aliased at /mcp, over Streamable HTTP. It supports protocol revisions 2025-11-25, 2025-06-18 and 2025-03-26. Both paths are POST-only, so a browser GET returning HTTP 405 is the intended behaviour.
• The OpenAPI 3.1 spec is at /openapi.json, for anything that consumes a spec instead of speaking MCP.
• The skill files are /agents/claude-skill.md and /agents/chatgpt-instructions.md, for an assistant that takes written instructions.

Discovery files sit beside them: /.well-known/mcp.json, /.well-known/ai-plugin.json and /.well-known/ucp, plus /llms.txt and /llms-full.txt for a model with no tool access. The human-readable version of all of this is the agents page.

What does each of the five tools return?

• quote_cost_segregation_study estimates what a cost segregation study would be worth on one US property: the depreciable basis after land, the 5-, 7-, 15- and 27.5-or-39-year breakdown, and first-year depreciation with and without a study. It is read-only.
• get_cost_segregation_pricing returns the published fees and what each product includes and excludes.
• get_cost_segregation_benchmarks returns reclassification bands by property type as planning ranges, with their stated limitations. They are planning bands, not percentiles and not a promise for any one building.
• get_cost_segregation_provider_facts returns the facts a buyer uses to compare firms, including what is not offered.
• book_cost_segregation_consult is the only tool that writes. It records a real request, emails our team and returns a scheduling link and a reference code. It takes no payment. An assistant should call it only after the person has asked to speak to someone.

Two details save a wrong answer. Rates in the quote come back as decimal fractions, so 0.40 means 40%, and the payload says so in a units block. And with no acquisition or construction-start date supplied, the bonus rate falls back to the placed-in-service-year phase-down; supply acquiredDate or constructionStartDate to apply the current test, under which 100% bonus depreciation under IRC §168(k) is permanent for qualified property acquired after January 19, 2025.

What does the quote return for an Opportunity Zone property's depreciation and recapture?

Setting isOpportunityZone: true leaves the depreciation arithmetic unchanged and adds the conditions that decide whether the deduction is usable and whether recapture arrives. A cost segregation study moves cost into 5-, 7- and 15-year property on an Opportunity Zone building exactly as it does anywhere else; what differs is the investor's basis and the exit.

The response returns five conditions; the two that decide the most are these. First, an investor's initial basis in a Qualified Opportunity Fund interest bought with deferred gain is zero under IRC §1400Z-2(b)(2)(B), which can suspend the accelerated deduction at the partner level under IRC §704(d) unless partnership liabilities allocated under IRC §752 supply basis. Second, after a 10-year hold, the IRC §1400Z-2(c) fair-market-value basis election can exclude gain on a qualifying disposition, including the depreciation recapture an accelerated schedule would otherwise produce; on a sale before the 10-year hold, §1245 recapture on the short-life property is ordinary income as it is anywhere else. The longer treatment is in our guide to Opportunity Zone cost segregation.

What are the rate limits?

They are per tool and per IP, and they are not uniform:

• quote_cost_segregation_study: 60 requests a minute.
• get_cost_segregation_pricing, get_cost_segregation_benchmarks and get_cost_segregation_provider_facts: 120 a minute each.
• book_cost_segregation_consult: 5 a minute, deliberately tight, because every success writes a row and emails a person.

Over MCP there is a second ceiling: the MCP endpoint itself allows 60 requests a minute per IP, and every POST counts toward it, including initialize and tools/list. Budget an MCP client against 60 a minute across the session. The step-by-step connection guide, with the one command for Claude, is in how to connect an agent to the cost segregation MCP server.

What can these tools not do?

They cannot order, buy or pay for a cost segregation study, and they do not return a finished one. A delivered study replaces every estimated number with an amount traced to a document the owner supplied, so the work starts with documents and a person, not with an API call. The reasoning is set out in whether an agent can order a cost segregation study and in where the human review sits.

They also do not decide whether a study is worth doing. The quote returns an assessment block that says whether the property clears the roughly $500,000 depreciable-basis guideline, and names the two conditions it cannot check. Cost segregation accelerates deductions; over the life of the building the same basis is recovered either way. A study tends to pay only above roughly $500,000 of depreciable basis, when the owner can use the deduction this year given their passive-activity position, and when the hold is long enough to outrun recapture. If you are comparing firms on the same questions, our comparison of cost segregation companies lists what to ask, and the qualifier puts a real property in front of a person.

Frequently Asked Questions

Is there an API for cost segregation estimates?

Yes. ClickDrag Finance publishes a JSON API under /api/agent/v1 with no API key: POST /estimate returns a first-year depreciation estimate for one US property with and without a cost segregation study, and GET /pricing, /benchmarks and /provider-facts return published pricing, planning bands by property type and provider facts. An estimate is not a completed study.

Is there an MCP server for cost segregation?

Yes. The ClickDrag Finance cost segregation MCP server is at https://www.clickdragfinance.com/api/mcp over Streamable HTTP, with no authentication, and exposes five tools. It supports MCP protocol revisions 2025-11-25, 2025-06-18 and 2025-03-26.

Can an assistant order or pay for a cost segregation study through the API?

No. The only tool that writes is book_cost_segregation_consult, which records a request, emails our team and returns a scheduling link. It takes no payment and commits nothing about a study. A cost segregation study is priced and prepared from the owner's documents.

Does the cost segregation quote handle an Opportunity Zone property?

Yes, as conditions and not as different arithmetic. With isOpportunityZone set to true, the depreciation estimate is unchanged and the response adds five conditions, among them the zero initial basis rule of IRC §1400Z-2(b)(2)(B), which can suspend the deduction for an investor without other basis, and the IRC §1400Z-2(c) election that, after a 10-year hold, can exclude gain including depreciation recapture on a qualifying disposition.

What are the rate limits on the cost segregation API?

Per tool and per IP: 60 requests a minute for the depreciation quote, 120 a minute each for pricing, benchmarks and provider facts, and 5 a minute for the consult request. Over MCP, the endpoint also allows 60 requests a minute per IP across all calls.

Is there an OpenAPI spec for the cost segregation API?

Yes. The OpenAPI 3.1 description is at /openapi.json and is generated from the same contract as the MCP server, so the cost segregation tool descriptions in the spec and in an MCP client are the same text.