feat(t27f): visual-output rule -- initialize instructions and an inline verdict on every t27f SVG

[gHashTag]

What

The t27 MCP server now carries the visual-output rule from specs/t27mcp/visual_output.t27 (gHashTag/t27#10504):

• initialize returns instructions built from RULE_CLAUDE_CODE. Claude Code puts server instructions in the model's system prompt, so every session that loads this server is told: an answer that explains a spec, a flow, numbers or a piece of work carries one visual; in the desktop app it goes inline, otherwise the SVG path is opened in the pane, otherwise a markdown table.
• t27f_graph and t27f_view end with an inline: line, the spec's inline_source verdict: embed the SVG as it is, or redraw it 680 px wide from t27f_outline rows. The verdict comes from the drawing's own numbers (viewBox width, smallest font-size, bytes).
• t27-mcp/visual exports RULE_TRI_CLAW and the helpers, so TRI CLAW's chat prompt reads the same rule from the same spec.

Stacked on #26 (base t27mcp/one-service).

Files

File	Kind
wasm/visual_output.wasm, wasm/visual_output_table.mjs	generated (t27c gen-c + zig, t27c gen-js); steps and sha256 in wasm/BUILD
visual.mjs	glue, 24 lines: loads the wasm, joins the rule text, measures an SVG
server.mjs	+8 / -6: instructions, the inline: line, two tool descriptions
package.json	exports ./visual, ships the three files

visual.mjs and the server.mjs lines are hand-written JavaScript, so this PR needs the owner's owner-approved-foreign label.

Evidence (lab, node 20, at 5166b13)

• node smoke.mjs: rc 0, all checks pass.
• JSON-RPC over stdio, rc 0:
  • initialize carries "instructions":"Visual output (specs/t27mcp/visual_output.t27):\n- Every answer that explains a spec, ...
  • t27f_graph fixture 1: inline: redraw it 680 wide from t27f_outline rows (1860 wide, smallest text 13 px, 5923 bytes; ...)
  • t27f_view scene 3: inline: redraw ... (1280 wide, smallest text 15 px, 8557 bytes; ...)
  • t27f_view scene 3, look 0: inline: redraw ... (1280 wide, smallest text 20 px, 6839 bytes; ...)

All three tool drawings are too wide for their smallest text to read at 680 px, which matches the spec's measured tests.

🤖 Generated with Claude Code

[tri-claw]

Summary by t27-bees

This PR adds the visual-output rule from specs/t27mcp/visual_output.t27 to the t27 MCP server. The initialize response now includes instructions (the Claude Code rule text), and the t27f_graph/t27f_view tools append an inline: verdict line derived from the generated SVG's viewBox width, smallest font-size, and byte size.

Worth a look

• server.mjs:778 — The initialize handler now returns instructions: ruleClaudeCode. If visual.mjs fails to load (e.g., WASM missing, import error), the server will crash on startup instead of degrading gracefully.
• visual.mjs:15 — inlineNote extracts viewBox width via regex /viewBox="0 0 (\d+)/. If the SVG uses single quotes, different spacing, or a non-zero origin (e.g., viewBox="10 10 800 600"), the width parse returns 0, forcing a redraw verdict incorrectly.
• visual.mjs:16 — Smallest font-size defaults to 0 when no font-size="..." attributes exist. Per the spec, 0 px means "never embedded", so any SVG without explicit font-size attributes will always get the redraw verdict.
• visual.mjs:3 — W._initialize() is called at module load time. If the WASM module lacks _initialize (e.g., build mismatch), the import of visual.mjs throws, breaking server.mjs and any consumer (including TRI CLAW) that imports it.
• wasm/BUILD:337 — The rebuild instructions say "never on the owner's Mac" but the generated visual_output.wasm and visual_output_table.mjs are committed. If the checked-in artifacts drift from the source spec (visual_output.t27), the runtime behavior will diverge from the spec's tests.

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