# Per Agent Skill Listing Dedupe

> Keep skill-listing deltas scoped per agent or thread so each agent gets its own first-turn announcement surface.

- Skill: `vishuwa2004/per-agent-skill-listing-dedupe` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add vishuwa2004/per-agent-skill-listing-dedupe`
- Raw SKILL.md: https://api.skillmd.com/api/skills/vishuwa2004/per-agent-skill-listing-dedupe/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: vishuwa2004 (https://skillmd.com/u/vishuwa2004)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/vishuwa2004/per-agent-skill-listing-dedupe

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# SKILL: Per-Agent Skill Listing Dedupe
**Domain:** attachment-pipeline
**Trigger:** Use when a multi-agent runtime must announce new skills or capabilities without one thread's deltas erasing another thread's initial listing.
**Source Pattern:** Distilled from reviewed per-agent capability-announcement tracking implementations.

## Core Method
Track which skill names were already sent to each agent separately rather than globally. Each agent or thread gets its own seen-set keyed by a stable agent identity, so the main thread announcing a listing does not make every subagent believe it already saw the same surface. When building the delta list for a given agent, compare only against that agent's set and update that set after sending.

## Key Rules
- Store a distinct seen-set per agent or thread, including a stable identity for the main thread.
- Filter outgoing skill deltas against the target agent's seen-set, not a global pool.
- Keep the per-agent seen-set alive for the lifetime of that agent so resumes and follow-up turns reuse its own state.
- Update the agent's seen-set immediately after sending new skills so later deltas stay accurate.

## Example Application
If a subagent is spawned in the middle of a long-running coding session, start it with its own empty seen-set. Even though the main thread already announced the skill surface, the subagent still gets a proper first-turn listing because its own history starts blank.

## Anti-Patterns (What NOT to do)
- Do not keep one global seen-set; that makes every new agent believe everything was already announced.
- Do not let one agent reuse another agent's seen-set; cross-agent sharing collapses the whole point of per-thread deltas.