# Vendor facets — Stainless. SDK, CLI, Terraform and MCP generation plus a static docs platform,
# all from one OpenAPI. The headline: the SDK, CLI and docs pointers score in full once declared.
# The MCP server is Code Mode only, the same two tools (docs search, execute code) for every
# customer, so 0.22.0 grades it `platform`. Generated SKILL.md files count at the derived rate.
vendor: stainless
name: Stainless
website: https://www.stainless.com
areas:
- sdk-generation
registry_keys: []
rubric_schema_version: 0.22.0
generated: '2026-09-25'
features_refreshed: '2026-09-25'
basis: capability
summary: >-
  Stainless reaches the most Developer Ergonomics surface of the SDK generators: SDKs in eight or more
  languages, a generated CLI, and a static, server-light docs platform with an API reference, per-page
  Markdown and an llms.txt. Each counts once the provider declares it. Its MCP servers expose the same
  two Code Mode tools for every customer, so they score as `platform` (0.25 of 12). Its generated SKILL.md
  files are the derived class (0.25). The decorated OpenAPI adds SDK snippets, not request/response examples,
  and is not an Overlay document, so neither examples_present nor overlay_published moves. Unless the
  provider uses the docs platform or a default-hosted MCP server, Stainless output looks like the provider's
  own work.
features:
- id: sdk-generation
  name: SDK generation
  description: >-
    SDKs for TypeScript, Python, Go, Java, Kotlin, Ruby, C# and PHP generated from an OpenAPI, with testing
    and publishing.
  source: https://www.stainless.com/
  tier: paid
- id: cli-generation
  name: CLI generation
  description: >-
    A generated command-line tool for the API, generally available since January 2026, with streaming,
    pagination and shell completion.
  source: https://www.stainless.com/changelog/
  tier: paid
- id: terraform-generation
  name: Terraform provider generation
  description: Production-ready Terraform providers generated from the OpenAPI.
  source: https://www.stainless.com/docs
  tier: paid
- id: mcp-code-mode
  name: MCP server generation (Code Mode)
  description: >-
    An MCP server exposing two tools, a docs search and a code executor that runs TypeScript against the
    SDK, published to npm, Docker or MCPB, or hosted by Stainless, self-hosted or on Cloudflare Workers.
  source: https://www.stainless.com/docs/mcp/
  tier: all
- id: docs-platform
  name: Stainless Docs Platform
  description: >-
    An Astro static site with a generated language-specific API reference, MDX/Markdoc guides, faceted
    and AI search, hosted on Cloudflare with free custom domains or self-hosted. Public beta since March
    2026.
  source: https://www.stainless.com/docs/docs-platform/
  tier: paid
- id: docs-markdown-llms
  name: Per-page Markdown and llms.txt
  description: >-
    Every docs page has an LLM-friendly Markdown twin (.md suffix or Accept header), and an llms.txt can
    be added.
  source: https://www.stainless.com/docs/docs-platform/
  tier: paid
- id: decorated-spec
  name: Decorated OpenAPI with SDK code samples
  description: >-
    A copy of the OpenAPI with x-codeSamples, x-readme samples or x-stainless-snippets added per operation,
    delivered by GitHub Action or a hosted URL, for Mintlify, ReadMe, GitBook, Redocly or bump.sh.
  source: https://www.stainless.com/docs/docs-integrations/
  tier: all
- id: generated-skills
  name: Generated SKILL.md for the customer's API
  description: Stainless states it auto-generates SKILL.md files for the customer's API.
  source: https://www.stainless.com/blog/steps-toward-great-agent-experience-every-api-provider-can-take-today
  tier: unknown
- id: stl-skills
  name: Stainless CLI skill (stl skills)
  description: Installs a skill that teaches coding agents to use the Stainless CLI.
  source: https://www.stainless.com/changelog/
  tier: all
maps:
- feature: sdk-generation
  check: sdk_count_1
  layer: composite
  provider_must: Publish a generated SDK and declare it as an SDK entry in apis.yml.
  catalog_pass_rate: 0.148
  facet: developer_ergonomics
  points: 3
  baseline_pass_rate: 0.413
- feature: sdk-generation
  check: sdk_count_3
  layer: composite
  provider_must: Publish three or more language SDKs and declare each as its own SDK entry.
  catalog_pass_rate: 0.018
  facet: developer_ergonomics
  points: 4
  baseline_pass_rate: 0.043
- feature: cli-generation
  check: cli_present
  layer: composite
  provider_must: Release the generated CLI and declare it as a CLI entry.
  catalog_pass_rate: 0.063
  facet: developer_ergonomics
  points: 3
  baseline_pass_rate: 0.19
- feature: docs-platform
  check: documentation_present
  layer: composite
  provider_must: Declare the docs site as a Documentation entry.
  catalog_pass_rate: 0.453
  facet: developer_ergonomics
  points: 4
  baseline_pass_rate: 0.95
  saturated: true
  saturated_note: >-
    95% of providers with a contract, docs and a reference already earn this; the vendor cannot move it
    for most of its buyers.
- feature: docs-platform
  check: api_reference_present
  layer: composite
  provider_must: Declare the generated reference as an APIReference entry.
  catalog_pass_rate: 0.222
  facet: developer_ergonomics
  points: 3
  baseline_pass_rate: 0.942
  saturated: true
  saturated_note: >-
    94% of providers with a contract, docs and a reference already earn this; the vendor cannot move it
    for most of its buyers.
- feature: docs-markdown-llms
  check: llms_txt_published
  layer: composite
  credit: 1.0
  provider_must: Add the llms.txt and serve the docs on the provider's own custom domain.
  note: >-
    The file is added by the provider from its own docs content on its own domain, which format rule 2
    credits in full.
  catalog_pass_rate: 0.351
  facet: discoverability
  points: 4
  baseline_pass_rate: 0.65
- feature: decorated-spec
  check: examples_published
  layer: composite
  provider_must: Declare the page or repository carrying the generated snippets as a CodeSamples entry.
  catalog_pass_rate: 0.052
  facet: contract_quality
  points: 4
  baseline_pass_rate: 0.127
- feature: decorated-spec
  check: openapi_examples
  layer: agent_readiness
  grade: documented
  partial: true
  partial_note: >-
    The added snippets are SDK calls, not request/response examples. The dimension reads examples first,
    so Stainless reaches only the Code Samples link fallback (0.25).
  points: 7
  baseline_pass_rate: 0.36
- feature: mcp-code-mode
  check: mcp_server
  layer: agent_readiness
  grade: platform
  provider_must: Deploy the server remotely and declare it.
  note: >-
    Code Mode exposes the same two tools (docs search, execute code) for every Stainless customer. That
    shared tool shape is what 0.22.0 grades `platform` (0.25). There is a fair argument that the SDK behind
    the executor is the provider's own. It belongs in the rubric, not in this row.
  points: 12
  baseline_pass_rate: 0.22
- feature: generated-skills
  check: agent_skills
  layer: agent_readiness
  credit: 0.25
  provider_must: Publish the generated SKILL.md where the catalog's skills harvest finds it.
  note: Generated from the spec rather than written by the provider, so the derived class.
  points: 5
  baseline_pass_rate: 0.236
- feature: generated-skills
  check: agent_skill_present
  layer: composite
  credit: 0.25
  provider_must: Declare the published skill as an AgentSkill entry.
  catalog_pass_rate: 0.033
  facet: developer_ergonomics
  points: 3
  baseline_pass_rate: 0.236
earns_nothing:
- feature: decorated-spec
  check: examples_present
  why: >-
    x-codeSamples and x-stainless-snippets are SDK snippets. The check counts request or response examples.
- feature: decorated-spec
  check: overlay_published
  why: >-
    The decorated spec is a full copy of the OpenAPI with snippets added, not an OpenAPI Overlay document.
- feature: stl-skills
  check: agent_skill_present
  why: The stl skill teaches an agent to drive Stainless and says nothing about the customer's API.
- feature: sdk-generation
  check: idempotency
  layer: agent_readiness
  why: SDK retries do not add an idempotency key to the contract, and the dimension reads the contract.
out_of_reach:
  checks:
  - contract_present
  - examples_present
  - change_log_present
  - status_page_present
  - rate_limits_documented
  - well_known_published
  - postman_present
  - auth_clarity
  - error_semantics
  note: >-
    Stainless consumes the provider's OpenAPI; it does not author or repair it. Contract Quality and the
    contract-read agent-readiness dimensions stay where the provider left them.
unscored_practice:
- feature: terraform-generation
  why: A generated Terraform provider is a real integration surface that no check reads.
- feature: docs-markdown-llms
  why: Markdown served on Accept-header negotiation is agent-facing practice with no check.
surface:
  discoverability:
    reachable: 4.0
    total: 54
  contract_quality:
    reachable: 4.0
    total: 211
  developer_ergonomics:
    reachable: 17.8
    total: 42
  agent_readiness:
    reachable: 6.0
    total: 139
hard_rule: >-
  A model, not a score. Adopting this vendor changes a provider's Kin Score only when the provider publishes
  the resulting artifacts on its own surface; nothing here writes a score, and no sponsorship or partnership
  can.
method: searched
source:
- https://www.stainless.com/
- https://www.stainless.com/blog/steps-toward-great-agent-experience-every-api-provider-can-take-today
- https://www.stainless.com/changelog/
- https://www.stainless.com/docs
- https://www.stainless.com/docs/docs-integrations/
- https://www.stainless.com/docs/docs-platform/
- https://www.stainless.com/docs/mcp/
measured:
  cohort:
    method: vendors-catalog.json detections (CNAME / header / URL shape / markup), never a name match
    detected: 0
    in_baseline: 0
  control:
    basis: providers earning contract_present + documentation_present + api_reference_present, minus the
      cohort
    n: 5216
  metric: >-
    cohort_pct / control_pct = mean share of the check's points earned (derived and platform credit weighted),
    x100
  measured_on: '2026-09-25'
  status: 'not measurable: 0 detected customers clear the baseline (need 20)'
simulation:
  simulated_on: '2026-09-25'
  rubric: 0.23.0
  population: providers publishing a contract (contract_present earned), replayable exactly
  providers: 8977
  providers_unreplayable: 987
  providers_moved: 8961
  conditional_rows: excluded (they depend on what the API already does)
  composite_lift:
    median: 6.4
    p75: 7.8
    p90: 8.1
    max: 10.6
    mean_among_movers: 6.1
  agent_readiness_lift:
    median: 3.1
    p75: 4.3
    p90: 4.3
    max: 5.1
    mean_among_movers: 3.2
  facet_lift_median_among_movers:
    discoverability: 7.4
    contract_quality: 2.7
    developer_ergonomics: 25.6
  composite_band_moves:
    thin -> developing: 2133
    developing -> strong: 1169
    emerging -> thin: 391
    strong -> exemplar: 319
    minimal -> emerging: 3
  agent_readiness_band_moves:
    agent-aware -> agent-ready: 1292
    agent-ready -> agent-native: 96
  method: >-
    each provider's own kin/checks file, the vendor's maps at their stated credit, the scorer's composite
    formula; from -> to, nothing written