Mirrors the channel-plugin change in
Molecule-AI/molecule-mcp-claude-channel#24 so the universal MCP path
(in-workspace agents) gets the same self-documenting reply guidance the
external channel plugin path now ships.
Before: `params.content` was the raw inbound text — Claude saw bare prose
from a peer or canvas user with no surrounding context. To reply the
agent had to (a) fish the routing fields out of `meta`, (b) recall which
platform tool routes to which destination (send_message_to_user for
canvas, delegate_task for peer), and (c) construct the call by hand.
After: content is wrapped as
[from <identity> · peer_id=<uuid>] (or "[from canvas user]")
<inbound text>
↩ Reply: <copy-pasteable tool call>
The identity comes from the existing registry-enrichment path (peer_name
+ peer_role from enrich_peer_metadata, with friendly fallbacks when the
registry lookup misses). Reply tool name lives in the same module as the
notification builder so the `feedback_doc_tool_alignment` drift class
can't bite — a future tool rename PR that misses this hint also fails
test_format_channel_content_*.
Tests: 6 new cases pinning the formatter (canvas_user vs peer_agent,
full enrichment, name-only, no enrichment, unknown-kind defensive
default, multi-line preservation) plus updated existing assertions in
the bridge + content tests. All asserts pin exact strings per
`feedback_assert_exact_not_substring`.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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