[hallerite]

After a sampled </assistant> or 〈|EOS|〉, Laguna XS.2 and M.1 bridges append the next role immediately, producing </assistant><user> where the checkpoint template requires </assistant>\n<user>.

Append the missing separator as unsampled scaffolding after a clean stop. Preserve the sampled prefix and the existing truncated-turn closure. The existing bridge suite now covers both checkpoints, user/tool continuations, both stop tokens, and truncated completions.

Validation: 8 new seam cases failed before the fix; all 12 pass afterward. The complete bridge, Laguna M.1, and Laguna XS-2.1 suites pass: 175 passed, 36 existing skips. Ruff, formatting, and pre-commit passed.

Stacked on the tool-string fix solely to provide the prerequisite base for #188; this PR's own diff contains only the Laguna fix and its regression cases.

Note

Fix LagunaXS2Renderer.bridge_to_next_turn to separate turns after clean stops

When the prior prompt and completion end with an assistant-end or EOS token, bridge_to_next_turn in laguna_xs2.py now emits a newline at the start of the extension before the next message. The synthesized assistant-end and newline for turns without a stop token are unchanged. Adds a parametrized test in test_bridge.py covering assistant-end, EOS, and missing-stop cases followed by user or tool messages, checking that prior tokens are preserved and the extension starts with the expected separator.

• Behavioral Change: bridges after a clean stop now start the extension with a newline instead of joining directly to the next message opening.

^{Macroscope summarized ec216ed.}