# Api Round Message Grouping

> Split conversation history into API-round buckets so compaction retries cut only the chunks tied to the failed round.

- **Type:** Skill
- **Install:** `agentstack add skill-ychampion-cskill-agents-api-round-message-grouping`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [ychampion](https://agentstack.voostack.com/s/ychampion)
- **Installs:** 0
- **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [ychampion](https://github.com/ychampion)
- **Source:** https://github.com/ychampion/cskill-agents/tree/main/agents/claude-code/skills/api-round-message-grouping
- **Website:** https://x.com/YashasGunderia/status/2039990540016693692?s=20

## Install

```sh
agentstack add skill-ychampion-cskill-agents-api-round-message-grouping
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# SKILL: API Round Message Grouping
**Domain:** context-management
**Trigger:** When compacting or retrying requests, use API-round boundaries instead of human-turn heuristics to determine what past messages belong together.
**Source Pattern:** Distilled from reviewed session memory, compaction, and context-budgeting implementations.

## Core Method
Walk the message stream and emit a new bucket every time a fresh assistant message with a new message id starts. This respects the API contract that all tool results complete before the next assistant response, so each bucket represents exactly one API round-trip; malformed conversations still fall through because the grouping only fires when a real assistant boundary appears. Downstream compaction retries can then drop or replay whole rounds without breaking tool-result pairing.

## Key Rules
- Track the last assistant message id and start a new group only when it changes while at least one message is already buffered.
- Push the final bucket at the end so the last API round isn’t lost.
- Do not split mid-assistant stream (IDs stay constant across streaming chunks), keeping each API response intact.
- Let dangling tool uses remain in the same group rather than inventing extra boundaries; downstream helpers (ensureToolResultPairing) repair them only when needed.
- Name each bucket explicitly when logging so retry diagnostics can report the round that triggered the fallback.

## Example Application
When a compaction attempt hits prompt-too-long, first group the transcript into API rounds, identify the round that introduced the oversized assistant response, and drop or compact only that round before retrying.

## Anti-Patterns (What NOT to do)
- Do not group by user turns or by time because API chunks can span multiple user messages and tool results.
- Do not start a new group on every assistant chunk; the streaming assistant may emit multiple chunks with the same `id`, and splitting them would leave incomplete tool-result pairs.

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [ychampion](https://github.com/ychampion)
- **Source:** [ychampion/cskill-agents](https://github.com/ychampion/cskill-agents)
- **License:** MIT
- **Homepage:** https://x.com/YashasGunderia/status/2039990540016693692?s=20

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-ychampion-cskill-agents-api-round-message-grouping
- Seller: https://agentstack.voostack.com/s/ychampion
- Browse the marketplace: https://agentstack.voostack.com/browse

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