iam

A development guide for Twilio's identity and access controls. Twilio is a service for building communications features such as calls, messages, and video into software.

In plain words
What is it for?
It helps authenticate Twilio APIs, manage API keys and subaccounts, rotate authentication tokens, create client access tokens, and diagnose 401 or 403 errors.
Why use it?
It helps developers choose suitable credentials, control account access, and investigate authentication and permission errors. It also covers safer credential rotation and account separation.

Skill for Claude CodeCodex

Part of the twilio-claude-plugin plugin — 31 skills, 18 commands, 7 agents, 5 hooks shipped together

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/wittyreference/twilio-claude-plugin/iam
Any agent
npx skills add wittyreference/twilio-claude-plugin --skill iam
Clone the repo
git clone --depth 1 https://github.com/wittyreference/twilio-claude-plugin

Made for: Claude Code, Codex.

Or install twilio-claude-plugin, the plugin that ships this one along with the rest of its 31 skills, 18 commands, 7 agents, 5 hooks.

Per session 8 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,181 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 1 finding. 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 $0.00008 $0.04181
Opus 5 $0.00004 $0.02090
Sonnet 5 $0.00002 $0.00836
Haiku 4.5 $0.00001 $0.00418

Measured 2d ago against content hash baa0c14fa782, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade C, and why

iam scanned grade C with 1 finding 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 2d ago.

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.

Hidden instructionshighPrompt injection

Directives inside HTML comments, invisible characters or bidirectional overrides are read by the model and not by the person reviewing the file.

- **Subaccounts cannot create sub-subaccounts** — Error 21101 "Subaccounts cannot contain subaccounts". The hierarchy is flat: one main account with up to 1000 direct subaccounts. <!-- verified: POST /Accounts.json from
skills/iam/SKILL.md · 253 lines

How it starts

The opening of the file, as written. The whole thing — 253 lines — stays where its author put it; the contents beside it link to each section on GitHub.


name: iam description: Twilio IAM development guide. Use when choosing authentication methods, managing API keys, rotating auth tokens, creating subaccounts, generating Access Tokens for client SDKs, or debugging 401/403 errors.

Twilio IAM

Authentication, authorization, and account hierarchy for Twilio APIs. Covers API key types (Standard, Main, Restricted), Access Tokens for client SDKs, auth token rotation, subaccount isolation, test credentials, and Public Key Client Validation (PKCV).

Evidence date: 2026-03-27. Account prefix: AC...

Scope

CAN

  • Authenticate via three methods: Account SID + Auth Token, API Key + Secret, or PKCV (Enterprise/Security)
  • Create Standard API keys via v2010 REST API or MCP tools
  • Create Restricted API keys via v1 IAM API with fine-grained per-endpoint permissions
  • Create Main API keys via Console only (not REST API)
  • Rotate auth tokens via secondary token creation and promotion (zero-downtime)
  • Generate Access Tokens (JWT) for Voice, Video, Sync, and Conversations client SDKs
  • Manage subaccounts: create, suspend, close, reactivate (main account only)
  • Transfer phone numbers between subaccounts using main account credentials
  • Use test credentials for free API testing (4 endpoints, magic phone numbers)
  • List/fetch/update/delete keys via REST API or MCP tools (list_api_keys, get_api_key, create_api_key, update_api_key, delete_api_key)
  • Manage signing keys via MCP (list_signing_keys, create_signing_key, delete_signing_key)
  • Upload PKCV public keys via Credentials API (POST /v1/Credentials/PublicKeys)
  • Use API key auth for all standard API operations (calls, SMS, phone numbers, etc.)
  • Use secondary auth token for authentication while rotating primary

Read the full file on GitHub · 253 lines

Files

What ships with it

2 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. 2d ago First seen · 253 lines · 8 tokens per session scan C baa0c14fa782

Subscribe to this mod's changes

iam is a skill published in the GitHub repository wittyreference/twilio-claude-plugin (2 stars, last pushed 3mo ago), licensed MIT. It adds 8 tokens to every session and 4,181 once invoked, about $0.0000 per session on Opus 5. A static security scan graded it C with 1 finding (hidden instructions). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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