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A2A Artifact Handoff
x402
A2A Artifact Handoff is a paid API for AI agents from a2a-artifact-handoff.onrender.com, paid per call via x402, $0.25/call, status unknown (last checked 2026-09-15).
Compiles agent outputs against a receiver contract and returns a verified, time-limited handoff package for agent-to-agent artifact transfer.
Price / call$0.25
Success—
StatusUnknown
How this service works
Compile agent outputs against a receiver contract and return a verified handoff package.
Output
A verified handoff package containing the compiled agent outputs validated against the receiver contract, including contract compliance status, artifact metadata (IDs, filenames, media types), handoff context (objective, decisions, assumptions, unresolved issues), source and destination agent identifiers, and a TTL-bounded expiry timestamp for the package.
Example use cases
Research agent passing findings to writer agent
“My research agent just finished gathering data and produced a markdown file called findings.md — can you compile it into a verified handoff package for the writer agent, with the objective 'compile competitive landscape research', a 24-hour TTL, and ensure it satisfies the writer agent's contract requiring a markdown artifact?”
Data pipeline stage handoff with SHA256 verification
“Package the outputs from my data-processing agent — a CSV file called results.csv — into a handoff bundle for the analytics agent, objective 'ETL stage 2 complete', with SHA256 verification required, max file size 500KB, and a 12-hour TTL.”
Multi-file code generation agent handoff
“My code-gen agent produced three files: main.py, utils.py, and requirements.txt — compile them into a verified handoff package for the code-review agent, with the objective 'initial scaffold generation done', decisions noting 'chose FastAPI over Flask', and a 72-hour TTL before the package expires.”
Technical details
Endpoint
POSThttps://a2a-artifact-handoff.onrender.com/v1/handoffs/compileWhen to prefer
Choose this endpoint when coordinating multi-agent pipelines where one agent's outputs must be formally handed off to another agent with contract compliance verification. It is the right choice when the receiving agent has declared a receiver contract specifying required file types, size constraints, or SHA256 integrity checks. Prefer this over ad-hoc file passing when auditability, TTL-bounded artifact lifecycle management, and structured handoff context (decisions, assumptions, unresolved issues) are required between pipeline stages.
Side effects
- Receiver contract validation failure — outputs do not satisfy requiredOutputs spec, returns contract mismatch error
- File size constraint violation — artifact exceeds maxFileBytes limit specified in contract constraints
- Invalid media type — submitted content type does not match contract expectations
- Missing required outputs — sourceOutputs array lacks entries matching receiver contract's requiredOutputs
- TTL out of range — ttlHours below 1 or above 720 returns validation error
- Empty or malformed content — neither content nor contentBase64 provided for an output item
- Payment failure — x402 USDC payment not completed, returns 402 Payment Required
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| ttlHours | integer | |
| sourceOutputs | array | |
| handoffContext | object | |
| receiverContract | object | Machine-readable input contract declared by the receiving agent. |
Tags
x402
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