fix: surface openrouter/fusion in the model picker

[fagramapp-star]

Summary

OpenRouter's meta-routers (openrouter/fusion, openrouter/fusion-flash) publish supported_parameters: [] in the /api/v1/models catalog because the concrete model is resolved per-request. They do support tool calling — verified against the live chat/completions endpoint with a function tool: the outer model (resolved to anthropic/claude-opus-5) returned finish_reason: tool_calls with a well-formed call.

_openrouter_model_supports_tools() treated the empty list as an explicit "no tools" declaration, so these routers were silently dropped from the model picker even though they work fine as the agent's driving model.

Changes

• _openrouter_model_supports_tools: treat an empty supported_parameters list like a missing field (permissive). Only a non-empty list that omits tools hides a model. An empty list carries no capability information.
• Add openrouter/fusion and openrouter/fusion-flash to the curated OPENROUTER_MODELS fallback list with short descriptions (including the ~4-5x cost caveat when the fusion panel is invoked).
• Tests: replaced test_empty_supported_parameters_list_drops_model with test_empty_supported_parameters_list_is_permissive (documents the fusion case) and added test_explicit_list_without_tools_drops_model to keep the original protection covered.

Test Plan

• tests/hermes_cli/test_models.py — 31 passed
• Live verification: POST /chat/completions with model: openrouter/fusion + a get_weather function tool returns tool_calls

Notes

The image-only-model protection from Kilo-Org/kilocode#9068 remains intact — those models advertise a non-empty parameter list without tools (e.g. google/gemini-3-pro-image-preview) and are still filtered.

[fattchris]

Updated — linked issue + PR template

Fixes #46064

What does this PR do?

OpenRouter's meta-routers (openrouter/fusion, openrouter/fusion-flash) publish supported_parameters: [] because the concrete model is resolved per-request. They do support tool calling — verified against the live endpoint.

_openrouter_model_supports_tools() treated the empty list as "no tools", silently dropping these routers from the model picker.

Type of Change

• 🐛 Bug fix (non-breaking)

Checklist

• Read Contributing Guide
• Conventional Commits (fix(models):)
• Searched for duplicates (found [Bug]: OpenRouter router models (openrouter/pareto-code, openrouter/fusion) are silently dropped from hermes model by the tool-support filter #46064 — this PR implements the claimed fix)
• PR contains only related changes
• pytest tests/hermes_cli/test_models.py -v — 31 passed
• Tests added (replaced drop test with permissive test, added explicit-list protection test)
• Tested on macOS 15.2 (Apple Silicon)

Notes

The image-only-model protection remains intact — those models advertise a non-empty parameter list without tools and are still filtered.

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Note: I can't update the PR title/body directly (authored from fagramapp-star fork, and the fattchris account doesn't have write access to the upstream repo). The correct conventional-commit title should be: fix(models): surface openrouter/fusion routers in model picker despite empty supported_parameters