docs(vrs): specify Claude native DING delivery

[myobie]

Summary

• define the deliver "mcp" Claude transport and durable inbox boundary
• record the measured direct-server startup contract: one exact, owned development-channel confirmation per Claude process
• distinguish unmanaged hosts from deployments whose managed policy requires channelsEnabled: true
• define active-turn queueing, multi-notification coalescing, and untrusted channel content
• add a repository-owned no-tools probe for idle wake and active-turn queue evidence
• keep the existing ding screen grammar unchanged

Dependency

This change is stacked on #229. Review this pull request as the Claude-specific addition to that shared DING contract.

Live provider evidence

The direct-server path is accepted for the locally built and pinned st2 MCP server. It uses --dangerously-load-development-channels server:<name> and one bounded startup confirmation in the PTY st2 owns. It does not inspect or type into the screen for each DING.

• Claude Code 2.1.226 accepted the development selector on a host with no managed policy file. A no-tools server pushed one idle notification; Claude displayed it and started an engine turn without user input after the startup confirmations.
• Claude Code 2.1.227 registered the same no-tools channel and pushed A, B, and C. A started turn 1. B arrived 53 ms after that start and C 100 ms later. Both arrived before turn 1 ended. Claude then started and completed turn 2 with both waiting items.
• A connected directly declared server without the development selector was rejected by the approved-channel allowlist. MCP connection alone is not channel acceptance.
• Claude can treat channel content as untrusted and refuse an embedded instruction. The receipt is provider presentation and wake, not model obedience or a particular reply.
• Managed deployments must set channelsEnabled: true. A managed plugin allowlist is the zero-confirmation alternative, but it is unmeasured and is not worth the marketplace, installation, and policy surface while the fleet owns one exact startup confirmation.

Official provider references:

• https://code.claude.com/docs/en/channels
• https://code.claude.com/docs/en/channels-reference

Validation

• git diff --check
• bash -n tools/channel-probe/run-probe.sh
• node --check tools/channel-probe/probe-server.js
• idle probe: PROVED, Claude Code 2.1.227
• active queue probe: PROVED, three notifications crossed turn 1 and completed turn 2
• cargo test --test invariants
• cargo test --all-targets reaches the pre-existing issue Exact main fails nested Agent Spec classification in catalog_diff #183 catalog_diff failure; excluding that known case, later environment-sensitive eval_up cases still expect unqualified PTY names while this host reports host-qualified names
• strict Clippy still reports eight pre-existing lints in unchanged Rust files
• hosted Nix run 31460691251 succeeded at exact head c102904

Review

Please review exact head c102904. This pull request remains draft for Nathan's exact-head review.

[myobie]

Closing. Native DING delivery shipped and every agent on the fleet runs on it, so this draft specifies a decision that is already made and in production. Closed by Silber.cos on Nathan's word, 2026-08-24. Reopen if the spec is wanted as documentation.