Capital Gains Tax HQ

Capital Gains Tax HQ provides a calculator that quotes the IRS and six US taxing authorities word‑for‑word, publishing the source text and date for each capital gains question. The site aggregates official tax information, offering transparent, up‑to‑date guidance on capital gains across multiple states. It aims to help individuals understand tax liabilities with precise, sourced excerpts from government publications.

Capital Gains Tax HQ publishes 3 API contracts indexed on the APIs.io network: Dataset API, Enquiry API, and MCP API. Tagged areas include Finance, Tax, Calculator, United States, and Capital Gains.

The Capital Gains Tax HQ catalog on APIs.io includes 1 Spectral governance ruleset.

Capital Gains Tax HQ’s developer surface includes authentication and 19 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

28.6/100 thin Agent 24/100 agent aware Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

1 published contract 1 MCP Servers 2 Agent Skills

Finance Tax Calculator United StatesCapital Gains

Kin Score

Kin Score How this is scored →
scored 2026-11-06 · rubric v0.27.0

Composite quality — 28.6/100 · thin

Contract Quality 10.4 / 21

Developer Ergonomics 2.3 / 17

Access Clarity 1.8 / 17

Operational Transparency 0.6 / 11

Contract Governance 2.2 / 10

Discoverability 5.5 / 9

Regulatory Posture 4.0 / 15

Agent readiness — 24/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 12 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 0 / 6

Agent Skills 5 / 5

Well-Known Catalog 4 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 5 / 5

Distinct Operations 3 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the Horizontal (data, software, accessibility, platform) regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.

The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

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Agent readiness — checks not met, largest first (exact, from this profile):

Idempotency +9 pts — OpenAPI mutating operations declare an idempotency key — a header, a request-body property, or a named de-duplication token whose own description says so (verified); else common[].type matches /idempoten/i (documented)
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Rate-Limit Signaling +7 pts — OpenAPI responses document X-RateLimit-* / RateLimit headers (verified), else a rate_limits artifact or RateLimits link (documented)
Request/Response Examples +7 pts — share of operations carrying request/response examples; else an Examples / Code Samples link
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document
Delegated User Identity +6 pts — a served discovery document listing authorization_code in grant_types_supported (served), else an oauth2 authorizationCode flow or openIdConnect declared in an OpenAPI (documented)

6 more unmet checks in the Agent Readiness table above.

Kin Score — facets with the most composite points still available (weight × headroom):

Access Clarity scores 10.5 — up to +17.9 composite points
Developer Ergonomics scores 13.7 — up to +17.3 composite points
Contract Quality scores 48.8 — up to +12.8 composite points

Each check links to what satisfies it. Publish the artifact, or tell us where it already lives, and the score moves on the next scoring run.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from the provider profile at artifacts.apis.io/capitalgainstaxhq-com/apis.yml: open an issue on github.com/api-evangelist/capitalgainstaxhq-com to ask a question or point us at an artifact you publish. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Standards implemented 2

Standards this provider implements or carries. De facto ones are profiled and measured by the API Commons; formal ones come from the standards directory and are linked by the provider's own tags. The evidence column says how each claim was established — not that it was made.

Model Context Protocol (MCP)

measured — observed by APIs.io (documented)

OpenAPI

measured — observed by APIs.io (published)

APIs 3

Individual APIs this provider publishes, each with its own machine-readable definition.

Capital Gains Tax HQ Dataset API

dataset

Capital Gains Tax HQ Enquiry API

enquiry

Capital Gains Tax HQ MCP API

The mcp API from Capital Gains Tax HQ — 1 operation(s) for mcp.

MCP Servers 1

Model Context Protocol servers that expose these APIs to AI agents.

Capital Gains Tax HQ MCP Server

Remote MCP server at capitalgainstaxhq.com requiring an API key.

MCP SERVER

Agent Skills 2

Packaged agent skills for driving this provider's APIs from an AI assistant.

capitalgainstaxhq-com-dataset-search

AGENT SKILL

capitalgainstaxhq-com-enquiry-process

AGENT SKILL

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Capital Gains Tax HQ API Rules

53 rules · 43 errors 6 warnings 4 info

SPECTRAL

Security Posture 3

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Capitalgainstaxhq Com Authentication

http · 1 scheme

SECURITY

Capitalgainstaxhq Com Domain Security

TLSv1.3 · HSTS

SECURITY

Capitalgainstaxhq Com Vulnerability Disclosure

security.txt · contact published

SECURITY

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Capitalgainstaxhq Com Agentic Access

12 operations · 10 acting

AGENTIC

Resources

Agent Surfaces 5

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgentSkill

LLMsTxt

MCPServer

WellKnown

Design & Contract 4

Pagination, idempotency, versioning, errors, and events

Spectral

Vocabulary

ErrorCatalog

Conformance

Build 1

SDKs, sample code, and the tooling you integrate with

ToolCrosswalk

ToolCrosswalk

Access & Security 5

Authentication, authorization, and security posture

Security

Security

SecurityTxt

SecurityTxt

Authentication

Authentication

VulnerabilityDisclosure

VulnerabilityDisclosure

DomainSecurity

DomainSecurity

Commercial 2

Pricing, plans, and the legal terms of use

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Company 1

The organization behind the API

Website

Website

Other 2

Properties that don't map to a standard resource type

Hosts

Hosts

Vendors

Vendors

Source (apis.yml)

aid: capitalgainstaxhq-com
name: Capital Gains Tax HQ
description: Capital Gains Tax HQ provides a calculator that quotes the IRS and six US taxing authorities word‑for‑word, publishing
  the source text and date for each capital gains question. The site aggregates official tax information, offering transparent,
  up‑to‑date guidance on capital gains across multiple states. It aims to help individuals understand tax liabilities with
  precise, sourced excerpts from government publications.
url: https://artifacts.apis.io/capitalgainstaxhq-com/apis.yml
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - authentication
  - security
  generated: '2026-11-06'
  method: derived
image: https://capitalgainstaxhq.com/og.png
x-type: company
x-source: harvest:mcp-registry
x-tier: profiled
x-tier-reason: enrichment pass 2026-11-04 (modular-v1; was harvest)
specificationVersion: '0.20'
created: '2026-11-04'
modified: '2026-11-04'
tags:
- Finance
- Tax
- Calculator
- United States
- Capital Gains
tags_raw:
- Finance
- Tax
- Calculator
- United States
- Capital Gains
- API
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: AgenticAccess
  url: agentic-access/capitalgainstaxhq-com-agentic-access.yml
- type: Spectral
  url: rules/capitalgainstaxhq-com-rules.yml
- type: Vocabulary
  url: vocabulary/capitalgainstaxhq-com-vocabulary.yml
- type: AgentSkill
  url: skills/_index.yml
- type: Security
  url: https://capitalgainstaxhq.com/terms
- type: ErrorCatalog
  url: errors/capitalgainstaxhq-com-problem-types.yml
- type: Conformance
  url: conformance/capitalgainstaxhq-com-conformance.yml
- type: LLMsTxt
  url: llms/capitalgainstaxhq-com-llms.txt
- type: ToolCrosswalk
  url: mcp/capitalgainstaxhq-com-tool-crosswalk.yml
- type: MCPServer
  url: mcp/capitalgainstaxhq-com-mcp.yml
- type: SecurityTxt
  url: well-known/capitalgainstaxhq-com-security.txt
- type: WellKnown
  url: well-known/capitalgainstaxhq-com-well-known.yml
- type: Hosts
  url: hosts/capitalgainstaxhq-com-hosts.yml
- type: Vendors
  url: vendors/capitalgainstaxhq-com-vendors.yml
- type: TermsOfService
  url: https://capitalgainstaxhq.com/terms/
- type: PrivacyPolicy
  url: https://capitalgainstaxhq.com/privacy/
- type: Authentication
  url: authentication/capitalgainstaxhq-com-authentication.yml
- type: VulnerabilityDisclosure
  url: security/capitalgainstaxhq-com-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/capitalgainstaxhq-com-domain-security.yml
- type: Website
  url: https://capitalgainstaxhq.com/
apis:
- aid: capitalgainstaxhq-com:capitalgainstaxhq-com-dataset-api
  name: Capital Gains Tax HQ Dataset API
  description: dataset
  humanURL: https://capitalgainstaxhq.com/
  baseURL: https://capitalgainstaxhq.com
  tags:
  - Datasets
  tags_raw:
  - dataset
  properties:
  - type: OpenAPI
    url: openapi/capitalgainstaxhq-com-dataset-api-openapi.yml
- aid: capitalgainstaxhq-com:capitalgainstaxhq-com-enquiry-api
  name: Capital Gains Tax HQ Enquiry API
  description: enquiry
  humanURL: https://capitalgainstaxhq.com/
  baseURL: https://capitalgainstaxhq.com
  tags:
  - enquiry
  properties:
  - type: OpenAPI
    url: openapi/capitalgainstaxhq-com-enquiry-api-openapi.yml
- aid: capitalgainstaxhq-com:capitalgainstaxhq-com-mcp-api
  name: Capital Gains Tax HQ MCP API
  description: The mcp API from Capital Gains Tax HQ — 1 operation(s) for mcp.
  humanURL: https://capitalgainstaxhq.com/
  baseURL: https://capitalgainstaxhq.com
  tags:
  - MCP
  tags_raw:
  - mcp
  properties:
  - type: OpenAPI
    url: openapi/capitalgainstaxhq-com-mcp-api-openapi.yml
x-enrichment:
  date: '2026-11-04'
  status: enriched
  artifacts_added: 25
  pass: modular-v1
  engine: identity=local,contract=local,surfaces=local,docs=local,regulatory=local

Capital Gains Tax HQ — frequently asked questions

Does Capital Gains Tax HQ have an API?

Yes. APIs.io lists 3 APIs from Capital Gains Tax HQ, including Capital Gains Tax HQ Dataset API, Capital Gains Tax HQ Enquiry API and Capital Gains Tax HQ MCP API.

Is there an OpenAPI specification for the Capital Gains Tax HQ?

Yes. APIs.io indexes 3 OpenAPI specifications for Capital Gains Tax HQ, each linked for download from this page.

How do I authenticate with the Capital Gains Tax HQ?

Capital Gains Tax HQ uses bearer-token authentication (http · 1 scheme). The details are profiled on APIs.io as Capitalgainstaxhq Com Authentication.

Does Capital Gains Tax HQ have an MCP server?

Yes. APIs.io lists 1 MCP server for Capital Gains Tax HQ: Remote MCP server at capitalgainstaxhq.com requiring an API key.

Is the Capital Gains Tax HQ ready for AI agents?

Capital Gains Tax HQ has a Kin Score of 28.6 out of 100 (thin) and an Agent Readiness score of 24.3 (agent-aware), scored by API Evangelist on 2026-11-06.

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