agent-first-http 0.1.0

Persistent HTTP client for AI agents — one request, one JSON line
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Agent-First HTTP

Persistent HTTP client for AI agents — one request, one JSON line.

Supported platforms: macOS, Linux, Windows.

curl opens a new TCP+TLS connection for every request. An agent making 20 calls to the same API pays 20 handshakes — on a 200ms RTT link, that's over 4 seconds of pure overhead before a single byte of useful work. afhttp is a long-lived process: connections stay open, concurrent requests share them, and the agent never thinks about transport.

CLI Mode

The default mode — one request, one JSON response, exit:

afhttp GET https://api.example.com/users
# {"code":"response","status":200,"body":[...],"trace":{"duration_ms":120,...}}

afhttp POST https://api.example.com/users --body '{"name":"Alice","email":"alice@example.com"}'
# {"code":"response","status":201,"body":{"id":42},...}

afhttp GET https://api.example.com/data --header "Authorization: Bearer sk-xxx"
# {"code":"response","status":200,...}

Exit codes: 0 = got HTTP response (any status), 1 = transport error, 2 = invalid arguments.

Pipe Mode

For long-lived sessions with connection reuse, concurrent requests, and WebSocket — use afhttp --pipe:

afhttp --pipe <<'EOF'
{"code":"config","defaults":{"headers":{"x-api-key":"sk-ant-xxx","anthropic-version":"2023-06-01"}}}
{"code":"request","id":"models","method":"GET","url":"https://api.anthropic.com/v1/models"}
{"code":"request","id":"usage","method":"GET","url":"https://api.anthropic.com/v1/usage"}
{"code":"request","id":"chat","method":"POST","url":"https://api.anthropic.com/v1/messages","body":{"model":"claude-opus-4-6","max_tokens":256,"messages":[{"role":"user","content":"Hello"}],"stream":true},"options":{"chunked":true,"chunked_delimiter":"\n\n"}}
EOF

output:

{"code":"config","defaults":{"headers":{"x-api-key":"[redacted]","anthropic-version":"2023-06-01"}},...}
{"code":"response","id":"models","status":200,"body":{"data":[{"id":"claude-opus-4-6",...}]},"trace":{"duration_ms":92,"http_version":"h2","redirects":0,"remote_addr":"13.32.4.10"}}
{"code":"response","id":"usage","status":403,"body":{"error":{"type":"permission_error","message":"Your API key does not have permission"}},"trace":{"duration_ms":87,"http_version":"h2","redirects":0}}
{"code":"chunk_start","id":"chat","status":200,"headers":{"content-type":"text/event-stream"}}
{"code":"chunk_data","id":"chat","data":"event: content_block_delta\ndata: {\"delta\":{\"text\":\"Hello\"}}"}
{"code":"chunk_data","id":"chat","data":"event: content_block_delta\ndata: {\"delta\":{\"text\":\" there\"}}"}
{"code":"chunk_data","id":"chat","data":"event: message_stop\ndata: {}"}
{"code":"chunk_end","id":"chat","trace":{"duration_ms":834,"chunks":8}}

What just happened:

  • One bash call — the heredoc sends all requests into one afhttp process; afhttp exits when stdin closes
  • Auth set once — the config header applies to every subsequent request; nothing is repeated
  • Three requests fired without waiting — models, usage, and chat all in-flight simultaneously
  • Connection reuse is automatic — requests to the same host can reuse pooled connections without extra agent logic
  • Out-of-order responses — usage arrived before chat finished; the agent matches by id
  • Streaming inline — chat delivers events as they arrive, no buffering, no special setup
  • HTTP errors are data — usage returned 403; afhttp delivers it as code: "response" with status: 403; the agent checks status, not exception types or text patterns

MCP Mode

afhttp --mcp runs as a Model Context Protocol server, letting AI tools like Claude Desktop make HTTP requests directly:

{
  "mcpServers": {
    "afhttp": { "command": "afhttp", "args": ["--mcp"] }
  }
}

Claude can then call http_request and http_config tools. See docs/mcp.md for the full setup guide.

curl Compatibility

Drop-in replacement for curl scripts — afhttp understands curl flags and returns structured JSON instead of raw bytes:

afhttp curl -X POST https://api.example.com/users \
  -H "Authorization: Bearer sk-xxx" \
  -d '{"name":"Alice"}'
# {"code":"response","status":201,"body":{"id":42},...}

# or via symlink
# macOS/Linux
ln -s "$(command -v afhttp)" ~/bin/curl
# Windows PowerShell
New-Item -ItemType SymbolicLink -Path "$HOME\\bin\\curl.exe" -Target (Get-Command afhttp).Source
curl https://api.example.com/users   # → JSON output

Install

cargo install agent-first-http

Docs

License

MIT