curl · curl project

curl for AI Agents

Call HTTP APIs with explicit methods, headers, authentication, retries, and failure handling.

Official toolOperational risk: R0–R3verified

Install for an Agent Report broken data

Agent readiness

84/100

Evidence confidence

verified

Documentation checked

2026-07-10

Independently tested version

8.7.1

Install for an Agent

Choose an official installation path that matches the runtime. Pin a version for team or CI use, then record the version before the first task.

HomebrewRecommended

macos · linux

$ shell

brew install curl

winget

windows

$ shell

winget install cURL.cURL

Authentication and Minimum Permissions

Grant only the permissions the task needs. Pass credentials through environment variables or a platform secret store, never through prompts, repositories, or logs.

Authentication requiredHeadless authentication supported

Pass scoped tokens through environment-backed headers and never print request secrets.

Methods: none, basic, bearer token, client certificate, netrc
Secret environment variables: HTTP_TOKEN
Credential storage: For headless runs, inject HTTP_TOKEN from the CI or platform secret manager at process start. For local interactive use, prefer the CLI or operating-system credential store when the official client supports one. Never save values in repository files.

Agent and Environment Compatibility

Confirm shell access first, then check the platform, network boundary, and credential path.

claude-codecodexgemini-clicopilot-cli

Environments: local, ci, container, headless, remote
Platforms: macos, linux, windows

Structured Output for Reliable Automation

Prefer a machine-readable format. Treat stdout as the result channel and stderr as diagnostics so the agent can parse failures separately.

response body · headers · JSON when returned by server

Use --fail-with-body or --silent or --show-error where supported and keep diagnostic logs on stderr.

--fail-with-body--silent--show-error

Independently captured output sample

8.7.1 · macOS 26.5.1 (arm64), local non-interactive shell

Executed command

curl --fail --silent --show-error --max-time 5 file://$PWD/package.json | jq -c '{name,private}'

Captured stdout · json

{"name":"clifinder-net","private":true}

Sample JSON Schema

{
  "type": "object",
  "additionalProperties": false,
  "required": [
    "name",
    "private"
  ],
  "properties": {
    "name": {
      "type": "string"
    },
    "private": {
      "type": "boolean"
    }
  }
}

R0–R3 Command Risk Guide

Risk is assigned per command. R0 is local or remote read-only, R1 is reversible local write, R2 changes remote state, and R3 can be irreversible or production-impacting.

Read-only does not mean public

R0 only means the command does not change local or remote state. A read-only command may still return secrets, identity data, configuration, or production data. Expose only the minimum needed for the task, and never place it in logs, prompts, or commits.

R0Read a JSON endpoint

Performs a failing-fast GET request and preserves the response body.

$ shell

curl --fail-with-body --silent --show-error --header "Accept: application/json" https://api.example.com/items

IdempotentSensitive output

R2Create a remote resource

Sends a state-changing POST request.

$ shell

curl --fail-with-body --request POST --header "Content-Type: application/json" --data @payload.json https://api.example.com/items

Confirmation requiredMay repeat a change

R3Delete a remote resource

Sends a potentially destructive DELETE request.

$ shell

curl --fail-with-body --request DELETE https://api.example.com/items/ID

Confirmation requiredMay repeat a change

How the Agent Readiness Score Is Built

Readiness describes how reliably an agent can operate the tool. It does not make every command safe and it does not replace an independent execution test.

Documentation indicates an agent-readiness score of 84/100. A bounded local smoke test is recorded for 8.7.1; review its limitations before relying on untested commands.

Structured output

Use --fail-with-body or --silent or --show-error where supported and keep diagnostic logs on stderr.

18/20

Headless operation

Official documentation describes a non-interactive authentication or execution path.

14/15

Safety controls

CLI Finder separates read commands from commands that require confirmation.

11/15

Determinism

Commands use explicit arguments and documented output controls where available.

8/10

Authentication

Pass scoped tokens through environment-backed headers and never print request secrets.

8/10

Documentation

This entry cites official documentation checked on 2026-07-10.

9/10

Installation

Official installation paths cover macOS, Linux, and Windows.

8/8

Maintenance

An official source repository is linked for release and maintenance review.

6/7

Agent artifacts

CLI Finder can generate registry-derived skills and policies; the tool itself was not credited with shipping them.

2/5

Generate a Skill or Agent Policy

Choose an agent and safety mode to generate a copyable artifact with installation, allowed commands, approval boundaries, and the evidence limitation.

Artifact typeTarget agentSafety mode

Generated artifact preview

SKILL.md

---
name: curl-agent-workflow
description: Use curl for HTTP APIs, file transfers, health checks with explicit command risk and evidence boundaries.
---

# curl agent workflow

Use this skill when the task needs HTTP APIs, file transfers, health checks, webhook calls.

## Evidence boundary

- Registry confidence: `verified`
- Documentation checked: `2026-07-10`
- Locally tested version: `8.7.1`
- Treat only the recorded executed checks as independently verified; every unlisted command remains documentation-only.

## Executed smoke checks

- `curl --version` — passed; exit 0. The recorded smoke check completed successfully.
- `curl --fail --silent --show-error --max-time 5 file://$PWD/package.json` — passed; exit 0. The recorded smoke check completed successfully.
- `curl --fail --silent --show-error --max-time 5 file://$PWD/package.json | jq -e '.name == "clifinder-net"'` — passed; exit 0. The bounded local file response passed the recorded jq assertion.
- `curl --fail --silent --show-error --max-time 5 file://$PWD/not-a-real-qa-file` — expected-failure; exit 37. curl returned its documented local-file open error and kept the diagnostic on stderr.

## Installation

- Homebrew (macos, linux): `brew install curl`
- winget (windows): `winget install cURL.cURL`

## Authentication

- Methods: none, basic, bearer token, client certificate, netrc
- Secret environment variables: `HTTP_TOKEN`
- Minimum permissions: Pass scoped tokens through environment-backed headers and never print request secrets.
- Credential storage: For headless runs, inject HTTP_TOKEN from the CI or platform secret manager at process start. For local interactive use, prefer the CLI or operating-system credential store when the official client supports one. Never save values in repository files.
- Never print, persist, or commit credential values.

## Allowed commands (read-only)

- `curl --fail-with-body --silent --show-error --header "Accept: application/json" https://api.example.com/items` — R0: Performs a failing-fast GET request and preserves the response body.

## Commands requiring explicit approval (read-only)

- None recorded.

## Forbidden commands (read-only)

- R2 `curl --fail-with-body --request POST --header "Content-Type: application/json" --data @payload.json https://api.example.com/items` — Sends a state-changing POST request.
- R3 `curl --fail-with-body --request DELETE https://api.example.com/items/ID` — Sends a potentially destructive DELETE request.

## Execution rules

1. Mode boundary: R0 exact commands may be used; R1, R2, and R3 commands are forbidden.
2. Confirm the selected account, project, context, database, namespace, or environment before any command.
3. Prefer structured output using `--fail-with-body`, `--silent`, `--show-error`.
4. Capture the exact command, exit code, stdout, and stderr separately.
5. A generated prefix policy must prompt unless that exact prefix is explicitly marked suffix-safe; do not infer safety from the executable name.
6. Never broaden credentials or disable safety controls to make a command succeed.

## Official sources

- [curl manual](https://curl.se/docs/manpage.html)
- [curl manual source repository](https://github.com/curl/curl)

CLI vs MCP vs API for This Task

CLI

Use the CLI on a developer machine, in CI, or in a container when the task should reuse existing shell state, credentials, and scripts and remain directly observable.

MCP

Consider MCP when the agent benefits from controlled tool definitions, delegated identity, or centrally governed server-side access.

API

Use the direct API for persistent application integrations, high-volume requests, or event-driven work where starting a process adds unnecessary overhead.

Read the full CLI vs MCP guide

Verification History and Official Evidence

CLI Finder records documentation review separately from real execution. Installation, help, exit codes, and output cannot be called Verified until they were run.

Current evidence boundary

Version output, a bounded local file response, a JSON assertion, and the missing-file failure path were executed with fail, silent, error, and timeout flags. No network, TLS, authentication, redirect, HTTP response failure, upload, or state-changing request was tested.

Evidence confidence: verified
Independently tested version: 8.7.1 · 2026-07-10
Test environment: macOS 26.5.1 (arm64), local non-interactive shell

Executed checks

PassedExit code: 0
curl --version
The recorded smoke check completed successfully.
stdout excerpt
curl 8.7.1 (x86_64-apple-darwin25.0) libcurl/8.7.1
PassedExit code: 0
curl --fail --silent --show-error --max-time 5 file://$PWD/package.json
The recorded smoke check completed successfully.
PassedExit code: 0
curl --fail --silent --show-error --max-time 5 file://$PWD/package.json | jq -e '.name == "clifinder-net"'
The bounded local file response passed the recorded jq assertion.
stdout excerpt
true
Expected failure pathExit code: 37
curl --fail --silent --show-error --max-time 5 file://$PWD/not-a-real-qa-file
curl returned its documented local-file open error and kept the diagnostic on stderr.
stderr excerpt
curl: (37) Couldn't open file <workspace>/not-a-real-qa-file