# AEVS (Agent Execution Verification System)

A Python SDK plus hosted backend that records every tool call a LangChain/LangGraph or MCP agent makes as a signed, hash-chained receipt, which anyone with the receipt ID can check through a public API or explorer.

- Category: App and agent security · by Fetch.ai
- Website: https://aevs.fetch.ai/
- Live data: no
- Checked on the official pages: 2026-10-24

## API

- Official API: yes, docs https://github.com/fetchai/AEVS-sdk/tree/main/docs
- Key needed: yes
- Price: not stated; limits: Beta; APIs and explorer may change. SDK truncates receipt payloads above 1 MB by default
- Base URL: https://api.aevs.fetch.ai/v1
- Formats: json

Example request:

```
https://api.aevs.fetch.ai/v1/public/receipts/stats
```

## Price and code

- Free tier: not stated
- Open source: https://github.com/fetchai/AEVS-sdk

## Data and license

- License: Apache License 2.0 (SDK); no service terms page found (https://github.com/fetchai/AEVS-sdk/blob/main/LICENSE); covers The Python SDK is Apache 2.0; terms for the hosted receipt backend and dashboard are not published on the site
- Commercial use unclear
- Credit: not stated
- Embedding unclear
- Quote (api_official): "Returns receipt metadata, hash-chain status, and KMS signature info." (https://aevs.fetch.ai/llms.txt)
- Quote (api_key): "Credentials from the dashboard at https://aevs.fetch.ai (sign up, register an agent)" (https://aevs.fetch.ai/llms.txt)
- Quote (api_key_verify): "Public receipts API (no auth; only agents with explorer listing enabled)" (https://aevs.fetch.ai/llms.txt)
- Quote (web_access): "Verify via API or explorer No account required. Same signed proof either way." (https://aevs.fetch.ai/)
- Quote (limits): "AEVS is in beta. APIs and explorer may change." (https://aevs.fetch.ai/)
- Quote (limits_payload): "`max_payload_bytes` — max receipt payload (default `1048576` = 1 MB); larger inputs/outputs are truncated." (https://aevs.fetch.ai/llms.txt)
- Quote (open_source): "Open source · fetchai/AEVS-sdk" (https://aevs.fetch.ai/)
- Quote (license): "Apache License Version 2.0, January 2004" (https://github.com/fetchai/AEVS-sdk/blob/main/LICENSE)
- Quote (proof_scope): "It proves the SDK recorded the call and its reported result — not that an external system actually performed the action." (https://aevs.fetch.ai/llms.txt)

## Rules for an agent

- pip install "aevs[langchain]" or "aevs[mcp]" (Python 3.10+), set AEVS_API_KEY and AEVS_AGENT_ID from the dashboard, call aevs.configure() then aevs.enable(), and aevs.flush() before exit; verify a receipt with GET https://api.aevs.fetch.ai/v1/receipts/verify/<reference_id>, no auth.
- Use receipt_visibility "private" or "proof_only" for personal or regulated data; "public" exposes full inputs and outputs to anyone with the reference_id
- Call aevs.flush() before a short-lived script exits or recent receipts may not be sent
- A receipt proves the SDK recorded the call, not that the external system performed it

## Agent access

- llms.txt: https://aevs.fetch.ai/llms.txt

Human page: https://agentgid.com/resources/aevs/
Source: AgentGid (agentgid.com). Facts are quoted from the site's own pages; check the license page before you ship.