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.
npx skills add CALLE-AI/awesome-phone-call-agents --skill holdfastgit clone --depth 1 https://github.com/CALLE-AI/awesome-phone-call-agentsWrote 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.
[](https://agentmods.dev/skills/calle-ai/awesome-phone-call-agents/holdfast)<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.
<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>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 | $0.01721 |
| Opus 5 | $0.00037 | $0.00860 |
| Sonnet 5 | $0.00015 | $0.00344 |
| Haiku 4.5 | $0.00007 | $0.00172 |
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 today.
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.
How it starts
The opening of the file, as written. The whole thing — 180 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, verified CALL-E call. It navigates menus with DTMF, waits through hold, talks to the human or automated system within a user-granted authorization scope, and reports a structured outcome that is cross-checked against transcript evidence. Every call that discovers menu paths contributes them back to a local IVR map library so the next call to the same organization is faster.
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 the result must come back as verified structured data, not vibes
- repeat calls to the same organization, where a saved IVR map saves time
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.
Core Workflow
Always follow these steps in order. The default mode is dry-run: plan and
preview only. A real call happens only after the user confirms the plan. For
a guided local run, scripts/run_task.py chains steps 1 through 7 in one
command (dry-run by default; --run places exactly one call after the
preview).
What ships with it
13 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.
- references/call-instructions.md 3.1 KB
- references/dtmf-playbook.md 3.2 KB
- references/examples.md 4.4 KB
- references/ivr-maps/_template.json 443 B
- references/ivr-maps/nws-boulder-denver.json 1.3 KB
- references/ivr-maps/nws-wilmington-oh.json 1.2 KB
- references/ivr-maps/README.md 2.0 KB
- references/safety.md 4.0 KB
- scripts/map_lookup.py 2.7 KB runs code
- scripts/map_update.py 5.8 KB runs code
- scripts/run_task.py 17 KB runs code
- scripts/test_run_task.py 6.8 KB runs code
- scripts/verify_result.py 6.7 KB runs code
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.
- today First seen · 180 lines · 74 tokens per session scan A 9e6e4c8a2b41
holdfast is a skill published in the GitHub repository CALLE-AI/awesome-phone-call-agents (88 stars, last pushed yesterday), licensed MIT. It adds 74 tokens to every session and 1,721 once invoked, about $0.0004 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 2026-09-12.
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