Problem

The dynamic tool schema filtering feature (#2020, PR #2026) added 752 lines across 17 files with a new ToolSchemaFilter struct, embedding-based tool selection, and config-driven always-on list. Despite thorough unit tests, the feature has zero live agent session coverage.

The feature is disabled in .local/config/testing.toml (no [agent.tool_filter] section with enabled = true).

Evidence

• CI-16 session (2026-03-20): grep 'tool schema filter' .local/testing/debug/session-ci16.log — empty
• Code path in assembly.rs: only fires when self.tool_schema_filter.is_some(), which requires config opt-in
• maybe_init_tool_schema_filter() returns early when config.enabled == false

Impact

Untested aspects:

1. Graceful degradation when embed() fails at startup (all tools fallback)
2. send_status("filtering tools...") spinner visibility in CLI/TUI
3. NoEmbedding fallback for late MCP tool registration
4. Actual token reduction in real sessions (the stated goal of research(tools): dynamic tool schema filtering to reduce context waste and improve selection accuracy #2020)
5. Interaction with MCP tool registration after startup
6. Top-K selection behavior with real tool descriptions

Proposed Fix

Add a live test session with [agent.tool_filter] enabled = true to validate the path. This requires an embedding-capable provider (OpenAI is available in testing config).

Optionally, enable the filter in .local/config/testing.toml:

[agent.tool_filter]
enabled = true
top_k = 5
always_on = ["memory_save", "memory_search", "shell"]

Note: enabling this in testing.toml will add latency at startup (embeds all tool descriptions).

Related

• Feature PR: feat(tools): dynamic tool schema filtering to reduce context waste and improve selection accuracy (#2020) #2026
• Issue: research(tools): dynamic tool schema filtering to reduce context waste and improve selection accuracy #2020
• Status command gap: enh(tools): /status should report tool_filter state when enabled #2028 (tool_filter state not shown in /status)