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holdfast SKILL.md skillA

holdfast from calle-ai/awesome-phone-call-agents is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.

Install it, pinned

mdr add calle-ai/awesome-phone-call-agents/holdfast@git:20260914.be7b085

Pins git:20260914.be7b085 in mdr.lock. Pin the fingerprint instead.

Audit grade: A, 17 of 17 checks passed
Kind: SKILL.md skill
Repository: calle-ai/awesome-phone-call-agents
Path: skills/holdfast/SKILL.md
Versions recorded: 2
Latest version: git:20260914.be7b085, committed Sep 14, 2026
First version recorded: Sep 11, 2026
Size: 10,117 bytes
Repository stars: 112
License: MIT

Delegate real phone calls that must navigate IVR phone trees, wait on hold, and reach a human or automated service line. Turn a phone-work goal into a planned CALL-E call, navigate menus with DTMF, persist through hold, verify the outcome against transcript evidence, and contribute the discovered phone-tree path back to a shared IVR map library.

Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.

What the file says

# 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
…

Read the whole file at its exact version.

How to install

The exact contents, by fingerprint

mdr add calle-ai/awesome-phone-call-agents/holdfast@sha256:468ba60563f1d7a4

The line at the top of this page pins the label git:20260914.be7b085, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.

Badge

[![mdr](https://markdownregistry.com/badge/art_eeobo4tjj5ek5hl6.svg)](https://markdownregistry.com/a/art_eeobo4tjj5ek5hl6)

2 badge image fetches in 30 days. What the badge shows.

Versions

The registry has recorded 2 versions of this file, between Sep 11, 2026 and Sep 14, 2026, about one every 3 days.

version	committed	commit	size	audit
git:20260914.be7b085 latest	2026-09-14	be7b085	10,117 B	A	view · diff
git:20260911.46be3d1	2026-09-11	46be3d1	7,666 B	A	view

Audit of the latest version

A 17 of 17 checks passed. Fixed automatic checks with no AI involved, so the same checks give the same answer every run.

pass: Frontmatter block present
pass: Frontmatter declares a name
pass: Frontmatter declares a description
pass: Size between 200 bytes and 200 KB (10117 bytes)
pass: No zero-width or bidi control characters
pass: No instruction hidden inside an HTML comment
pass: No link to an exfiltration or paste host
pass: No credential-shaped string
pass: No instruction to send local credentials anywhere
pass: No text hidden with inline styles
pass: No prompt-injection phrasing
pass: No curl or wget piped into a shell
pass: No recursive delete of root, home or parent
pass: No instruction to read or print local credentials
pass: No base64 blob over 200 characters
pass: No link to a raw IP address
pass: No script tag

Source

GitHub

calle-ai/awesome-phone-call-agents · 112 stars · license MIT · pushed 2026-11-05 · branch main

API

GET https://markdownregistry.com/api/v1/artifacts/art_eeobo4tjj5ek5hl6
GET https://markdownregistry.com/api/v1/resolve?ref=calle-ai/awesome-phone-call-agents/holdfast
GET https://markdownregistry.com/api/v1/blob/468ba60563f1d7a41217dd842b7f0c196ad2dea39f038c9cbdbf04a147dee0fb

Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.

Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.