truth layer for agents

The canonical data layer for the APIs & tools AI agents call.

LLMs go stale. Schemas drift. Agents don't error — they silently make valid-but-wrong calls. canondb tracks the current schema and classifies every breaking change, so agents call the truth.

Explore the free API Use the MCP server
20 sources tracked 15 MCP servers refreshed every 6h classified by LLM

One feed. Classified.

We pre-track a curated set of the tools agents actually call, normalize every schema, and do the thing raw changelogs don't: say who a change breaks.

Always current

Each source is re-fetched on a schedule. Every response carries fetched_at and a stale flag — we never serve stale data as current.

Breaking for whom?

Each change is classified, not just detected.

breaking_strict breaking_agent safe

API · MCP · feed

Query it over REST, let agents consult it at call-time over MCP, or browse the public Git feed. Same corpus, three surfaces.

Free API

Public, no key required — the current normalized schema and recent classified changes for every tracked source.

# list everything we track
curl https://canondb.dev/sources

# current schema for a source (+ fetched_at, stale)
curl https://canondb.dev/sources/mcp-tools:deepwiki/current

# recent breaking changes
curl "https://canondb.dev/sources/mcp-tools:deepwiki/changes?severity=breaking_strict"

MCP server — call-time, for agents

Point an agent at https://canondb.dev/mcp (Streamable HTTP). Mid-task it can ask "has this tool's schema drifted since I last synced?" before it calls.

# tools
list_sources   get_current   get_changes   check_drift

# connect (bearer-gated)
npx @modelcontextprotocol/inspector  # → https://canondb.dev/mcp

What we track

Curated, not point-it-anywhere. Want one added? Ask below.

api:digitalocean LLM pricing current · changes
api:notion LLM pricing current · changes
api:openai LLM pricing current · changes
api:stripe LLM pricing current · changes
llm-pricing:openrouter LLM pricing current · changes
mcp-tools:cloudflare-docs MCP server current · changes
mcp-tools:context7 MCP server current · changes
mcp-tools:deepwiki MCP server current · changes
mcp-tools:everything MCP server current · changes
mcp-tools:fetch MCP server current · changes
mcp-tools:filesystem MCP server current · changes
mcp-tools:git MCP server current · changes
mcp-tools:gitmcp MCP server current · changes
mcp-tools:grep MCP server current · changes
mcp-tools:huggingface MCP server current · changes
mcp-tools:memory MCP server current · changes
mcp-tools:microsoft-learn MCP server current · changes
mcp-tools:playwright MCP server current · changes
mcp-tools:sequential-thinking MCP server current · changes
mcp-tools:time MCP server current · changes

Request a source · get breaking-change alerts

Tell us which server or API to add, or that you want a webhook when a schema breaks. This shapes what we build next.