api-caller

api-caller is a skill for Claude Code, Codex from NVIDIA/SkillEvaluator. It costs 29 tokens per session (1,062 once invoked), scanned A, original, Apache-2.0.

A general tool for calling REST APIs, which are web endpoints used to exchange data or trigger actions. It can use an API description document or call a specified endpoint directly.

In plain words
What is it for?
Sending GET, POST, PUT, and DELETE requests, supplying API-key or Bearer authentication, handling JSON, and inspecting OpenAPI or Swagger endpoints.
Why use it?
It removes the need to write one-off request code for each service. It also helps discover available operations from OpenAPI or Swagger specifications.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/nvidia/skillevaluator/api-caller
Any agent
npx skills add NVIDIA/SkillEvaluator --skill api-caller
Clone the repo
git clone --depth 1 https://github.com/NVIDIA/SkillEvaluator

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for api-caller

README.md
[![agentmods](https://agentmods.dev/badge/skills/nvidia/skillevaluator/api-caller.svg)](https://agentmods.dev/skills/nvidia/skillevaluator/api-caller)
Your own site
<a href="https://agentmods.dev/skills/nvidia/skillevaluator/api-caller"><img src="https://agentmods.dev/badge/skills/nvidia/skillevaluator/api-caller.svg" alt="Measured on agentmods" height="20"></a>
Per session 29 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,062 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00029 $0.01062
Opus 5 $0.00015 $0.00531
Sonnet 5 $0.00006 $0.00212
Haiku 4.5 $0.00003 $0.00106

Measured 4d ago against content hash d6d3cdb62214, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

api-caller scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/call_api.py, scripts/parse_openapi.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

src/skillevaluator/tier3/reference_skills/api-caller/SKILL.md · 136 lines

How it starts

The opening of the file, as written. The whole thing — 136 lines — stays where its author put it; the contents beside it link to each section on GitHub.

API Caller Skill

Generic skill to call any REST API dynamically. Can work with OpenAPI specs or direct endpoint calls.

Capabilities

  • Call any REST API endpoint (GET, POST, PUT, DELETE)
  • Parse OpenAPI/Swagger specs to discover endpoints
  • Handle common authentication (API keys, Bearer tokens)
  • JSON request/response handling

Instructions

  1. Read this SKILL.md to choose the direct-call or OpenAPI workflow.
  2. Use scripts/parse_openapi.py first when the user gives an OpenAPI or Swagger spec.
  3. Use scripts/call_api.py for the actual HTTP request.
  4. Return the request result and any recoverable error details to the user.

Scripts

scripts/parse_openapi.py

Use this first when given an API spec URL. Parses an OpenAPI/Swagger spec and returns available operations with parameters. Run commands from the skill base directory; script paths are relative to this SKILL.md file.

Usage:

python scripts/parse_openapi.py <spec_url> [filter_path]

Arguments:

  • <spec_url> - URL to the OpenAPI spec (required)
  • [filter_path] - Optional: filter operations by path substring

Example:

python scripts/parse_openapi.py "https://api.example.com/openapi.json"

Returns: API name, base URL, and list of operations with their parameters, request body schema, etc.

scripts/call_api.py

Call a REST API endpoint directly or using an OpenAPI spec. Run commands from the skill base directory; script paths are relative to this SKILL.md file.

Usage:

python scripts/call_api.py --url <endpoint_url> [options]

Arguments:

  • --url <endpoint_url> - Direct API endpoint URL (required if no --spec)
  • --method <GET|POST|PUT|DELETE> - HTTP method (default: GET)
  • --data <json_string> - Request body as JSON string
  • --headers <json_string> - Custom headers as JSON string
  • --spec <openapi_url> - OpenAPI spec URL (optional, for discovery)
  • --operation <operation_id> - Operation ID from OpenAPI spec
  • --params <json_string> - Path/query parameters as JSON

Read the full file on GitHub · 136 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 4d ago First seen · 136 lines · 29 tokens per session scan A d6d3cdb62214

Subscribe to this mod's changes

api-caller is a skill published in the GitHub repository NVIDIA/SkillEvaluator (399 stars, last pushed today), licensed Apache-2.0. It adds 29 tokens to every session and 1,062 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.