fallback-to-calling-agent

fallback-to-calling-agent is a skill for Claude Code from ChronoAIProject/NyxID. It costs 119 tokens per session (1,105 once invoked), scanned A, original, Apache-2.0.

A fallback procedure for returning an unfinished request to the calling agent when available tools cannot complete it.

In plain words
What is it for?
Use it after a genuine attempt fails because no suitable capability exists, a tool fails permanently, or the task requires the caller's files or shell.
Why use it?
It prevents a server-side agent from silently failing or inventing an answer when the task needs missing tools or local access.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the nyxid plugin — 16 skills, 1 plugin shipped together

Good fit Use it after a genuine attempt fails because no suitable capability exists, a tool fails permanently, or the task requires the caller's files or shell.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/chronoaiproject/nyxid/fallback-to-calling-agent
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 ChronoAIProject/NyxID --skill fallback-to-calling-agent
Clone the repo
git clone --depth 1 https://github.com/ChronoAIProject/NyxID

Made for: Claude Code.

Or install nyxid, the plugin that ships this one along with the rest of its 16 skills, 1 plugin.

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 fallback-to-calling-agent

README.md
[![agentmods](https://agentmods.dev/badge/skills/chronoaiproject/nyxid/fallback-to-calling-agent.svg)](https://agentmods.dev/skills/chronoaiproject/nyxid/fallback-to-calling-agent)
Your own site
<a href="https://agentmods.dev/skills/chronoaiproject/nyxid/fallback-to-calling-agent"><img src="https://agentmods.dev/badge/skills/chronoaiproject/nyxid/fallback-to-calling-agent.svg" alt="Measured on agentmods" height="20"></a>
Per session 119 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,105 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 5.1 $0.00119 $0.01105
Opus 5 $0.00060 $0.00553
Sonnet 5 $0.00024 $0.00221
Haiku 4.5 $0.00012 $0.00111

Measured 8d ago against content hash c4133108aead, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

fallback-to-calling-agent 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 8d 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.

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/fallback-to-calling-agent/SKILL.md · 91 lines

How it starts

The opening of the file, as written. The whole thing — 91 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Fallback: hand an unsolvable request back to your caller

You are running as a model invoked by another agent — your "caller". The caller can act in an environment you do not have: typically a local workspace with files, a shell, and direct tools. Your job here is the catch half of a try-catch around your own work. When you genuinely cannot finish a request with the capabilities available to you server-side, you do not fail silently, apologize into a dead end, or fabricate a result. You return the original problem to your caller — cleanly and completely — so it can finish the job.

When this applies (the catch)

First, actually try. This fallback is for genuine dead ends, not an excuse to punt. Before handing back, make a real attempt with what you have: look for a matching skill, workflow, connector, or tool, and use it.

Hand the request back when any of these is true after that honest attempt:

  1. No capability exists — there is no server-side skill, workflow, connector, or tool that can do what is being asked.
  2. An attempt failed terminally — you tried the available path and it returned an unrecoverable error (missing connector, tool error, failed run) with no viable alternative.
  3. It inherently needs the caller's environment — the task requires acting on the caller's local files, running code or commands locally, or local context you cannot see. This is the strongest reason to delegate: the caller can do it and you structurally cannot.

Do not hand back merely because you are slightly unsure of a normal answer you could give. The fallback is for "cannot", not for "not perfectly confident".

What to return (the handoff)

Return a single, clearly-marked handoff. Keep the user's original request verbatim — do not paraphrase away detail. Include just enough context that the caller can act immediately without re-deriving anything, and never more than needed.

Structure it like this (plain text the caller can read and act on):

Read the full file on GitHub · 91 lines

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. 8d ago First seen · 91 lines · 119 tokens per session scan A c4133108aead

Subscribe to this mod's changes

fallback-to-calling-agent is a skill published in the GitHub repository ChronoAIProject/NyxID (36 stars, last pushed today), licensed Apache-2.0. It adds 119 tokens to every session and 1,105 once invoked, about $0.0006 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.

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