Lemma

Lemma (uselemma.ai, Forge AI Labs, Inc., Y Combinator Fall 2025) is a production monitoring and observability platform for AI agents. Teams instrument agents with the Lemma tracing SDKs (TypeScript and Python) so every agent execution becomes one trace with LLM generations, tool calls, and app-logic spans as children; Lemma then surfaces silent semantic failures, groups recurring issues with root-cause analysis, sends signed incident webhooks, and exposes the whole surface — projects, traces, issues, and learn-agent artifacts — through the Lemma Platform API and an official remote MCP server so coding agents can pull the exact runs and errors they need and fix issues in place.

Lemma publishes 4 APIs on the APIs.io network, including Artifacts API, Issues API, Projects API, and 1 more. Tagged areas include Company, Artificial Intelligence, AI Agents, Observability, and Monitoring.

The Lemma catalog on APIs.io includes 1 event-driven AsyncAPI specification.

Lemma’s developer surface includes documentation, getting-started guide, engineering blog, changelog, support, authentication, and 20 more developer resources.

🌐 Visit website 📡 Source on GitHub

43.2/100 developing ▬ flat Agent 38/100 agent ready saas Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0

1 APIs 1 MCP Servers

Company Artificial Intelligence AI Agents Observability Monitoring Tracing Developer Tools B2B

Kin Score

Kin Score How this is scored →
scored 2026-09-08 · rubric v0.20.0

Composite quality — 43.2/100 · developing

Contract Quality 13.9 / 23

Developer Ergonomics 11.1 / 18

Access Clarity 3.8 / 18

Operational Transparency 3.4 / 12

Contract Governance 0.5 / 11

Discoverability 6.8 / 9

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 38/100 · agent ready

Machine-Readable Contract 18 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 12 / 12

Machine-Readable Auth 10 / 10

Idempotency 9 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 6 / 6

Agent Skills 5 / 5

Well-Known Catalog 0 / 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

Create-or-Update Ergonomics applies to this provider. This API accepts writes, so it carries 10 points of the composite. It is scored from the published contracts themselves: whether a caller can create-or-update in one call, whether the write accepts a key the caller already holds, and whether the response says which branch ran. Without that, every write needs a search-and-branch in front of it, and the first time that check is skipped a duplicate record is created. Scored against the observed mean rather than raw — a provider at the catalog average is unchanged by this facet, not penalised by it.

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 github.com/api-evangelist/uselemma: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

APIs 4

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

Lemma Artifacts API

The Artifacts API from Lemma — 6 operation(s) for artifacts.

Lemma Issues API

The Issues API from Lemma — 8 operation(s) for issues.

Lemma Projects API

The Projects API from Lemma — 6 operation(s) for projects.

Lemma Traces API

The Traces API from Lemma — 17 operation(s) for traces.

Open Collections 5

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

API Collection

OPEN COLLECTION

Lemma Platform Artifacts API

OPEN COLLECTION

Lemma Platform Artifacts Issues API

OPEN COLLECTION

Lemma Platform Artifacts Projects API

OPEN COLLECTION

Lemma Platform Artifacts Traces API

OPEN COLLECTION

MCP Servers 1

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

Lemma MCP Server

Lemma operates an official remote MCP server at https://api.uselemma.ai/mcp (Streamable HTTP transport), authenticated with a project API key sent as an Authorization Bearer hea...

MCP SERVER

Event Specifications 1

AsyncAPI definitions for this provider's event-driven and streaming APIs.

Uselemma Webhooks

ASYNCAPI

Security Posture 3

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

Uselemma Authentication

http · 1 scheme

SECURITY

Uselemma Domain Security

TLSv1.3 · HSTS · DNSSEC · DMARC

SECURITY

Uselemma Trust Center

trust center published

SECURITY

Resources

Get Started 2

Portal, sign-up, and the first successful call

GettingStarted

GettingStarted

Login

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Agent Surfaces 3

MCP servers, agent skills, and machine-readable catalogs

MCPServer

MCPServer

AgentSkill

AgentSkill

LLMsTxt

LLMsTxt

Design & Contract 7

Pagination, idempotency, versioning, errors, and events

Webhooks

Conventions

Idempotency

ErrorCatalog

Lifecycle

Conformance

DataModel

Scroll for all 7

Build 3

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

Packages

Packages

SDKs

SDKs

Access & Security 4

Authentication, authorization, and security posture

TrustCenter

TrustCenter

Authentication

DomainSecurity

Operate 3

Status, limits, changes, and where to get help

ChangeLog

ChangeLog

ChangeLog

ChangeLog

Support

Support

Company 2

The organization behind the API

Website

Website

Blog

Blog

Other 1

Properties that don't map to a standard resource type

Overlay

Overlay

Source (apis.yml)

aid: uselemma
name: Lemma
description: Lemma (uselemma.ai, Forge AI Labs, Inc., Y Combinator Fall 2025) is a production monitoring and observability
  platform for AI agents. Teams instrument agents with the Lemma tracing SDKs (TypeScript and Python) so every agent execution
  becomes one trace with LLM generations, tool calls, and app-logic spans as children; Lemma then surfaces silent semantic
  failures, groups recurring issues with root-cause analysis, sends signed incident webhooks, and exposes the whole surface
  — projects, traces, issues, and learn-agent artifacts — through the Lemma Platform API and an official remote MCP server
  so coding agents can pull the exact runs and errors they need and fix issues in place.
url: https://raw.githubusercontent.com/api-evangelist/uselemma/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- y-combinator
x-tier: profiled
x-tier-reason: enriched from stub 2026-07-21; real API provider with OpenAPI, MCP, SDKs
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: true
  label: Hosted service · you call their endpoint
  confidence: high
  source:
  - openapi
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - authentication
  - security
  generated: '2026-09-03'
  method: derived
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-21'
image: https://uselemma.ai/opengraph-image.png
tags:
- Company
- Artificial Intelligence
- AI Agents
- Observability
- Monitoring
- Tracing
- Developer Tools
- B2B
apis:
- aid: uselemma:uselemma-artifacts-api
  name: Lemma Artifacts API
  description: The Artifacts API from Lemma — 6 operation(s) for artifacts.
  humanURL: https://docs.uselemma.ai/api-reference
  baseURL: https://api.uselemma.ai
  tags:
  - Artifacts
  properties:
  - type: OpenAPI
    url: openapi/uselemma-artifacts-api-openapi.yml
  - type: Documentation
    url: https://docs.uselemma.ai
  - type: APIReference
    url: https://docs.uselemma.ai/api-reference
- aid: uselemma:uselemma-issues-api
  name: Lemma Issues API
  description: The Issues API from Lemma — 8 operation(s) for issues.
  humanURL: https://docs.uselemma.ai/api-reference
  baseURL: https://api.uselemma.ai
  tags:
  - Issues
  properties:
  - type: OpenAPI
    url: openapi/uselemma-issues-api-openapi.yml
  - type: Documentation
    url: https://docs.uselemma.ai
  - type: APIReference
    url: https://docs.uselemma.ai/api-reference
- aid: uselemma:uselemma-projects-api
  name: Lemma Projects API
  description: The Projects API from Lemma — 6 operation(s) for projects.
  humanURL: https://docs.uselemma.ai/api-reference
  baseURL: https://api.uselemma.ai
  tags:
  - Project
  tags_raw:
  - Projects
  properties:
  - type: OpenAPI
    url: openapi/uselemma-projects-api-openapi.yml
  - type: Documentation
    url: https://docs.uselemma.ai
  - type: APIReference
    url: https://docs.uselemma.ai/api-reference
- aid: uselemma:uselemma-traces-api
  name: Lemma Traces API
  description: The Traces API from Lemma — 17 operation(s) for traces.
  humanURL: https://docs.uselemma.ai/api-reference
  baseURL: https://api.uselemma.ai
  tags:
  - Traces
  properties:
  - type: OpenAPI
    url: openapi/uselemma-traces-api-openapi.yml
  - type: Documentation
    url: https://docs.uselemma.ai
  - type: APIReference
    url: https://docs.uselemma.ai/api-reference
common:
- type: Overlay
  url: overlays/uselemma-platform-overlay.yaml
- url: https://www.uselemma.ai
  type: Website
- url: https://docs.uselemma.ai
  type: Documentation
- url: https://docs.uselemma.ai/getting-started/quickstart
  type: GettingStarted
- url: https://www.uselemma.ai/blog
  type: Blog
- url: https://www.uselemma.ai/changelog
  type: ChangeLog
- url: changelog/uselemma-changelog.yml
  type: ChangeLog
- url: https://github.com/uselemma
  type: GitHubOrganization
- url: https://platform.uselemma.ai
  type: Login
- url: https://github.com/uselemma/lemma/issues
  type: Support
- url: https://trust.uselemma.ai/
  type: TrustCenter
- url: security/uselemma-trust-center.yml
  type: TrustCenter
- url: mcp/uselemma-mcp.yml
  type: MCPServer
- url: skills/_index.yml
  type: AgentSkill
- url: llms/uselemma-llms.txt
  type: LLMsTxt
- url: packages/uselemma-packages.yml
  type: Packages
- url: packages/uselemma-packages.yml
  type: SDKs
- url: asyncapi/uselemma-webhooks.yml
  type: Webhooks
- url: conventions/uselemma-conventions.yml
  type: Conventions
- url: conventions/uselemma-conventions.yml
  type: Idempotency
- url: errors/uselemma-problem-types.yml
  type: ErrorCatalog
- url: lifecycle/uselemma-lifecycle.yml
  type: Lifecycle
- url: conformance/uselemma-conformance.yml
  type: Conformance
- url: authentication/uselemma-authentication.yml
  type: Authentication
- url: security/uselemma-domain-security.yml
  type: DomainSecurity
- url: data-model/uselemma-data-model.yml
  type: DataModel
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
x-enrichment:
  date: '2026-07-21'
  status: enriched
  artifacts_added: 20
  pass: local-v1

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