1c-ssl-skills: Skill for Claude Code

.agents/skills/long-horizon-prompting/SKILL.md

long-horizon-prompting is a skill for Claude Code, Codex from brake71/1c-ssl-skills. It costs 154 tokens per session (5,065 once invoked), scanned A, a copy of long-horizon-prompting, MIT.

A guide to writing the starting instructions for an autonomous agent expected to work for hours or days, alone or while coordinating other agents. It uses detailed task definitions, success conditions, and failure cases.

In plain words
What is it for?
Use it to write or review prompts for extended autonomous work, parallel agent runs, and difficult tasks whose success must be described clearly rather than checked by a simple test.
Why use it?
Long-running agents can spend substantial time producing an answer that only appears correct if the task is underspecified. This helps make the goal and acceptable outcomes precise before the run begins.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions subagents; installed under .agents/ (shared by several agents).

This is brake71/1c-ssl-skills's own configuration. It tells Claude Code and Codex how to work on 1c-ssl-skills itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything 1c-ssl-skills configures →

Reuse

Borrowing it

Nothing to install: this file belongs to brake71/1c-ssl-skills. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/brake71/1c-ssl-skills/main/.agents/skills/long-horizon-prompting/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/brake71/1c-ssl-skills

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.

agentmods badge for long-horizon-prompting

README.md
[![agentmods](https://agentmods.dev/badge/skills/brake71/1c-ssl-skills/long-horizon-prompting/github.svg)](https://agentmods.dev/skills/brake71/1c-ssl-skills/long-horizon-prompting)
Your own site
<a href="https://agentmods.dev/skills/brake71/1c-ssl-skills/long-horizon-prompting"><img src="https://agentmods.dev/badge/skills/brake71/1c-ssl-skills/long-horizon-prompting/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.

agentmods 80×15 button for long-horizon-prompting

Your own site · 80×15
<a href="https://agentmods.dev/skills/brake71/1c-ssl-skills/long-horizon-prompting"><img src="https://agentmods.dev/badge/skills/brake71/1c-ssl-skills/long-horizon-prompting.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 154 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,065 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 100% copy Near-identical to another mod 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 $0.00154 $0.05065
Opus 5.5 $0.00062 $0.02026
Sonnet 5.5 $0.00031 $0.01013
Haiku 4.5 $0.00015 $0.00507

Measured 17d ago against content hash 75f8c53453fb, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

long-horizon-prompting 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 17d 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.

Origin

This is a copy

100% identical to long-horizon-prompting — 91 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.agents/skills/long-horizon-prompting/SKILL.md · 275 lines

How it starts

The opening of the file, as written. The whole thing — 275 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Long-Horizon Prompting

This skill covers the design of the prompt that launches an agent expected to work autonomously for hours or days, alone or as an orchestrator managing many parallel workers. The central technique is the pseudo-formal task brief: a specification written with the rigor of formal verification but expressed linguistically, because most hard problems have no machine-checkable success condition. The exemplar is the published prompt behind GPT-5.6 Sol Ultra's candidate proof of the Cycle Double Cover Conjecture, produced by a 64-subagent orchestration (claim-long-horizon-cdc-run). The prompt structure generalizes far beyond mathematics: any domain where success can be stated precisely and failure modes can be enumerated can use the same brief anatomy.

The controlling trade-off: everything that makes a long run productive (persistence, autonomy, parallelism) also raises the cost of a weak specification. A short interactive prompt fails cheaply; a long-horizon brief with a loophole burns hours of compute producing an answer-shaped artifact that does not solve the problem.

When to Activate

Activate this skill when:

  • Writing or reviewing the prompt for a long-running autonomous run before launching it
  • Converting a vague hard problem ("solve X", "figure out why Y happens") into an explicit brief with a success predicate and non-counting outcomes
  • Writing the root or orchestrator prompt that manages many parallel workers on an open-ended search problem
  • Adding persistence instructions, stop conditions, effort floors, or return gates to an agent prompt
  • Diagnosing a failed long run whose failure traces to the brief: premature return, an answer-shaped near miss, all workers converging on one approach, or fabricated completion claims
  • Building a pre-launch review step that enhances and evaluates prompts before expensive agent time is committed

Do not activate this skill for adjacent work owned by other skills:

  • Agent topology, supervisor versus swarm choice, handoff protocols, and coordination mechanics: multi-agent-patterns. That skill owns the architecture; this skill owns the words that steer it.
  • Runtime control surfaces, locked evaluators, rollback, durable logs, and approval boundaries around an autonomous loop: harness-engineering. Constraints that must survive optimization pressure belong in the harness, not the prompt.
  • Building the evaluator, regression suite, or deterministic quality gates a run is scored by: evaluation.
  • LLM-as-judge design, rubrics, pairwise comparison, and bias mitigation: advanced-evaluation.
  • Compaction, note-taking, and cross-session memory mechanics for surviving context limits: context-compression, memory-systems, filesystem-context.
  • Loops that modify their own harness or prompts: self-improvement-loops.
  • Remote sandboxes and background execution infrastructure: hosted-agents.

Read the full file on GitHub · 275 lines

Files

What ships with it

4 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. 17d ago First seen · 275 lines · 154 tokens per session scan A 75f8c53453fb

Subscribe to this mod's changes

long-horizon-prompting is a skill published in the GitHub repository brake71/1c-ssl-skills (82 stars, last pushed 15d ago), licensed MIT. It adds 154 tokens to every session and 5,065 once invoked, about $0.0006 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to long-horizon-prompting, differing in 91 lines, and is treated as a copy.