Registers `dcode` (LangChain's deepagents-code) as a native Agent Plugin: root `plugin.json`
contributing the shared skill, the Hooks V2 SessionStart/UserPromptSubmit/Stop lifecycle, and the
`hindsight_*` MCP server, installed through Dcode's own marketplace/plugin manager.
Includes fixes found by running it against deepagents-code 0.1.65:
- Decode `last_assistant_message`. Dcode's transcript lags the Stop event, so that field is
load-bearing, but it is computed as `str(content)` — a Python repr whenever the provider returns
content blocks. It was retaining ~1.8KB of encrypted reasoning payload as the assistant turn, and
never comparing equal to the transcript's clean text, so an already-flushed reply was appended
again every turn. Guarded family-wide: any harness surfacing the field must declare a decoder.
- Annotate the six read-only MCP tools with `readOnlyHint`. Dcode rejects unannotated MCP calls in
headless mode, which made recall and the knowledge-page tools unusable under `dcode -n`.
- Parity: local history import (attributed via `dcode threads list --json`, since the transcripts
carry no cwd), a Docker E2E adapter and image, the harness icon on the docs site as well as the
control plane, and a clean uninstall that also retires the marketplace it registered.
- Document that Dcode cannot host the codebase survey: `hindsight_ingest_document` writes, so its
headless runtime gates it by design; it falls back to another agent's CLI like eight other
harnesses.
Supersedes #3887.
Co-authored-by: Paritoshdagar <paritoshdagar@gmail.com>
Claude-Session: https://claude.ai/code/session_01DNWFQn8AUN6SApcswHG3aN
Nicolò Boschi
