fix(flows): exempt workflow proposal tools from tokenjuice compaction (canvas renders ≥4-node graphs)

[graycyrus]

Summary

The workflow_builder copilot's proposal never reached the canvas for non-trivial graphs. Root cause: extract_workflow_proposal (ops.rs) reads the post-compaction agent history, but ToolOutputMiddleware::after_tool runs tinyjuice on every tool result first — and the JSON compressor tabulates any uniform node-array ≥3 rows / ~512 bytes into [json table: graph.nodes …], stripping the type:"workflow_proposal" marker. So serde_json fails, extraction returns None, has_proposal=false, blank canvas. Small graphs slipped under the threshold and rendered; ≥4-node graphs vanished (nondeterministically — one build recovered via tinyjuice_retrieve + re-propose, another silently died).

Solution

Exempt the proposal-/persistence-emitting tools (propose_workflow, revise_workflow, edit_workflow, save_workflow, create_workflow) from both compaction passes (payload summarizer + tokenjuice) in ToolOutputMiddleware::after_tool. Their output is a machine-readable contract that downstream extraction + the frontend canvas parse structurally; compacting it serves no purpose. The per-tool char cap and shared byte-budget backstop are untouched.

Testing

• 3 new extract_workflow_proposal tests (6-node graph survives, latest-of-many, ignores non-proposals).
• 5 new middleware tests — including a baseline test proving tokenjuice really tabulates + strips the marker for a non-exempt tool, then that every exempt tool stays byte-for-byte intact.
• openhuman::flows:: → 363 pass; openhuman::tinyagents::middleware:: → 39 pass.
• GGML_NATIVE=OFF cargo check clean; cargo fmt --check clean.

Acceptance criteria

• Repro gone — ≥4-node proposals extract intact → canvas renders deterministically
• Regression safety — baseline (tabulation happens) + fix (exempt tools intact) tests
• Diff coverage ≥ 80% on changed lines

Summary by CodeRabbit

• Bug Fixes

  • Preserved workflow proposal results so large or detailed proposals remain complete and can be processed correctly.
  • Ensured the latest workflow proposal is selected when multiple proposals are present.
  • Improved handling of tool outputs while maintaining safeguards for oversized content.
  • Confirmed sampling results retain their content during compaction while remaining subject to size limits.

• Tests

  • Added coverage for proposal extraction, output preservation, truncation, and non-proposal tool results.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 350b218f-eb66-4b63-a8f2-7b645730c070

📥 Commits

Reviewing files that changed from the base of the PR and between fe2a304 and e813fc4.

📒 Files selected for processing (2)

• src/openhuman/flows/ops_tests.rs
• src/openhuman/tinyagents/middleware.rs

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📝 Walkthrough

Walkthrough

ToolOutputMiddleware now exempts workflow proposals from compaction and truncation, exempts sampling tools from compaction only, and adds tests for payload preservation and workflow proposal extraction.

Changes

Workflow payload preservation

Layer / File(s)	Summary
Middleware exemption rules src/openhuman/tinyagents/middleware.rs	Tool-specific predicates conditionally skip summarization, TokenJuice compaction, character caps, and shared byte-budget truncation.
Middleware exemption tests src/openhuman/tinyagents/middleware.rs	Tests cover intact proposal payloads, normal non-exempt processing, oversized payload truncation, and sampling-tool behavior.
Workflow proposal extraction tests src/openhuman/flows/ops_tests.rs	Tests cover large proposals, latest-result selection, and histories without workflow proposals.

Estimated code review effort: 4 (Complex) | ~45 minutes

Sequence Diagram(s)

sequenceDiagram
  participant ToolResult
  participant ToolOutputMiddleware
  participant Compaction
  participant Truncation
  ToolResult->>ToolOutputMiddleware: provide tool name and payload
  ToolOutputMiddleware->>ToolOutputMiddleware: classify exemptions
  ToolOutputMiddleware->>Compaction: process non-exempt payloads
  ToolOutputMiddleware->>Truncation: truncate non-exempt payloads

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Possibly related PRs

• tinyhumansai/openhuman#4472: Adds the workflow proposal tool and UI consuming its output.
• tinyhumansai/openhuman#4887: Uses latest workflow proposal extraction during flow building.

Suggested labels: rust-core, bug

Suggested reviewers: senamakel

Poem

I’m a rabbit guarding graphs in JSON,
No token shears shall make them gone.
Proposals stay whole, samples stay clear,
The latest workflow hops near.
Tests thump softly: thump, thump, hooray!

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