A phone-call task for reaching organizations through automated menus, keypad prompts, and hold queues. It plans the call, carries it out with permission, and checks the reported result against the call transcript.

Use it for errands such as asking about a baggage claim, cancelling a membership, or contacting a utility company. It can remember discovered menu routes for repeat calls.

It removes the need to personally wait through phone trees and hold music. It also reduces unsupported claims by requiring evidence from the conversation.

holdfast — Skill for Claude Code and Codex by CALLE-AI

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.

Any agent

npx skills add CALLE-AI/awesome-phone-call-agents --skill holdfast

Clone the repo

git clone --depth 1 https://github.com/CALLE-AI/awesome-phone-call-agents

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/calle-ai/awesome-phone-call-agents/holdfast/github.svg)](https://agentmods.dev/skills/calle-ai/awesome-phone-call-agents/holdfast)

Your own site

<a href="https://agentmods.dev/skills/calle-ai/awesome-phone-call-agents/holdfast"><img src="https://agentmods.dev/badge/skills/calle-ai/awesome-phone-call-agents/holdfast/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/calle-ai/awesome-phone-call-agents/holdfast"><img src="https://agentmods.dev/badge/skills/calle-ai/awesome-phone-call-agents/holdfast.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 74 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 2,231 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00074	$0.02231
Opus 5.5	$0.00030	$0.00892
Sonnet 5.5	$0.00015	$0.00446
Haiku 4.5	$0.00007	$0.00223

Measured 1mo ago against content hash 468ba60563f1, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

holdfast 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 1mo ago.

The scan reads SKILL.md. This mod also ships 8 executable files (scripts/map_lookup.py, scripts/map_update.py, scripts/run_task.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.

skills/holdfast/SKILL.md · 218 lines

How it starts

The opening of the file, as written. The whole thing — 218 lines — stays where its author put it; the contents beside it link to each section on GitHub.

HoldFast

Use this skill when the user wants to delegate a real phone call to an organization whose line is behind an IVR phone tree, a hold queue, or an automated service line: "call the airline and ask about my baggage claim", "cancel my gym membership over the phone", "sit on hold with the utility company until a human picks up".

HoldFast turns a phone-work goal into one planned CALL-E call and an evidence-checked result. Its call instructions cover DTMF navigation, hold, and human or automated lines within a user-granted authorization scope; the result is cross-checked against transcript evidence. Calls may also produce a review-only IVR route proposal. A proposal never enters a later live call until a human approves it and it passes exact-goal and freshness checks.

When To Use

Use this skill for:

outbound calls the user initiates for their own errand, claim, booking, or account question
calls that must traverse an IVR menu, DTMF keypad prompts, or a hold queue
calls where returned structured fields need explicit transcript checks and unsupported values must remain unverified
repeat calls to the same organization, where a current human-reviewed map can guide navigation without treating unreviewed history as trusted

When Not To Use

Do not use this skill to:

place marketing, cold outreach, survey, or bulk calls to third parties
call emergency services, or handle medical, legal, or financial decisions beyond relaying logistics the user explicitly authorized
guess phone numbers, extensions, account identifiers, or identity details
agree to payments, contract changes, or cancellations beyond the exact scope the user authorized
keep retrying a failed call in a loop; fail closed and report instead

Prerequisites

HoldFast drives CALL-E through the local calle CLI. If the calle CLI is not installed or not authenticated, stop and run the CALL-E readiness flow first (see the CALL-E install guide and the official calle skill). Never print or expose tokens, plan identifiers, or confirmation tokens.

Read the full file on GitHub · 218 lines

Files

What ships with it

24 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.

1mo ago Changed · +38 lines 468ba60563f1
1mo ago First seen · 180 lines · 74 tokens per session scan A 9e6e4c8a2b41

Subscribe to this mod's changes

holdfast is a skill published in the GitHub repository CALLE-AI/awesome-phone-call-agents (112 stars, last pushed 4d ago), licensed MIT. It adds 74 tokens to every session and 2,231 once invoked, about $0.0003 per session on Opus 5.5. 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 2026-09-12.

Productivity

holdfast next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
holdfastCALLE-AI/awesome-phone-call-agents	Skill	112	4d ago	MIT	A	74	Claude Code, Codex
orbit-notionnexu-io/open-design	Skill	107k	yesterday	Apache-2.0	A	117	Claude Code, Codex
agentmailpaperclipai/paperclip	Skill	112k	today	MIT	A	30	Claude Code, Codex
Cortexdanielmiessler/LifeOS	Skill	20k	3d ago	MIT	A	184	Claude Code
rowboat-spacesrowboatlabs/rowboat	Skill	18k	yesterday	Apache-2.0	A	60	Claude Code, Codex
feishuHmbown/CodeWhale	Skill	41k	yesterday	MIT	A	33	Claude Code, Codex
pinchtab-mcppinchtab/pinchtab	Skill	11k	12d ago	MIT	A	52	Claude Code, Codex