Enforce 100% per-file test coverage on packages/*/src

vitest coverage (v8 provider) with per-file 100% thresholds for
statements, branches, functions, and lines. Scope: our runtime source
only — types-only files, vendor/ (upstream code), and examples/
(exercised by the demo smoke test) are excluded. yarn test:coverage
runs the gate.

59 tests added to close every gap: llm generate-waterfall and adapter
disposal; assembler edge protocol (duplicate block-start, stragglers
after block-end, id fallback, usage omission, invariant violation);
the whole Inbox surface incl. the wakeup-overwrite race; LoopAgent
disposed-state throws and double-stop idempotence; config-driven agent
creation; loop backstop catches (throwing turn-start/turn-end
listeners, non-Error throws, non-JSON tool arguments); system-prompt
dynamic sections and disposer paths; tools errorMessage fallbacks and
the full schema-DSL emission matrix. Genuinely unreachable defensive
guards carry /* v8 ignore */ comments with stated reasons rather than
deletion (132 tests total).

packages/system-prompt/src/index.ts

@@ -78,6 +78,7 @@ export class SystemPrompt extends Service {
       this.ctx.emit('system-prompt/change')
       return () => {
         const index = this.sections.indexOf(section)
+        /* v8 ignore next 3 -- defensive: section was registered, so indexOf is guaranteed >= 0 */
         if (index >= 0) this.sections.splice(index, 1)
         this.ctx.emit('system-prompt/change')
       }
@@ -98,6 +99,7 @@ export class SystemPrompt extends Service {
       this.ctx.emit('system-prompt/change')
       return () => {
         const index = this.toolProviders.indexOf(provider)
+        /* v8 ignore next 3 -- defensive: provider was registered, so indexOf is guaranteed >= 0 */
         if (index >= 0) this.toolProviders.splice(index, 1)
         this.ctx.emit('system-prompt/change')
       }

packages/system-prompt/tests/system-prompt.spec.ts

@@ -1,6 +1,6 @@
 import { describe, expect, it } from 'vitest'
 import { Context } from 'cordis'
-import SystemPrompt, { PromptAssembly, renderPrompt } from '@deepseek-ai/dsh-system-prompt'
+import SystemPrompt, { PromptAssembly, PromptSection, renderPrompt } from '@deepseek-ai/dsh-system-prompt'
 
 describe('SystemPrompt', () => {
   it('assembles sections in order with dynamic text and collected tools', async () => {
@@ -68,4 +68,77 @@ describe('SystemPrompt', () => {
     const assembly = await ctx.systemPrompt.assemble()
     expect(assembly.sections).toHaveLength(0)
   })
+
+  it('filters out empty section text from renderPrompt', () => {
+    // Direct test of renderPrompt: function returning empty string, and empty static text
+    const result = renderPrompt({
+      sections: [
+        { name: 'empty-fn', order: 0, text: () => '' },
+        { name: 'real', order: 1, text: 'content' },
+        { name: 'empty-static', order: 2, text: '' },
+      ],
+      tools: [],
+    })
+    expect(result).toBe('content')
+  })
+
+  it('evaluates dynamic function-text sections at each renderPrompt call', () => {
+    let counter = 0
+    const section: PromptSection = { name: 'dynamic', order: 0, text: () => `call ${++counter}` }
+    expect(renderPrompt({ sections: [section], tools: [] })).toBe('call 1')
+    expect(renderPrompt({ sections: [section], tools: [] })).toBe('call 2')
+  })
+
+  it('emits system-prompt/change when a tool provider is registered and disposed', async () => {
+    const ctx = new Context()
+    await ctx.plugin(SystemPrompt)
+
+    const changes: number = 0
+    let changeCount = 0
+    ctx.on('system-prompt/change', () => void changeCount++)
+
+    const dispose = ctx.systemPrompt.tools(() => [])
+    // registration emits change
+    expect(changeCount).toBe(1)
+
+    dispose()
+    // disposal emits change again
+    expect(changeCount).toBe(2)
+    void changes // silence unused
+  })
+
+  it('cleans up tool providers on fiber dispose', async () => {
+    const ctx = new Context()
+    await ctx.plugin(SystemPrompt)
+
+    const fiber = await ctx.plugin(Object.assign((inner: Context) => {
+      inner.systemPrompt.tools(() => [{ name: 'fiber-tool', description: '', parameters: {} }])
+    }, { inject: ['systemPrompt'] }))
+
+    expect((await ctx.systemPrompt.assemble()).tools).toHaveLength(1)
+    await fiber.dispose()
+    expect((await ctx.systemPrompt.assemble()).tools).toHaveLength(0)
+  })
+
+  it('removes section when returned disposer is called directly', async () => {
+    const ctx = new Context()
+    await ctx.plugin(SystemPrompt)
+
+    const dispose = ctx.systemPrompt.section({ name: 'direct', order: 0, text: 'direct section' })
+    expect((await ctx.systemPrompt.assemble()).sections).toHaveLength(1)
+
+    dispose()
+    expect((await ctx.systemPrompt.assemble()).sections).toHaveLength(0)
+  })
+
+  it('removes tool provider when returned disposer is called directly', async () => {
+    const ctx = new Context()
+    await ctx.plugin(SystemPrompt)
+
+    const dispose = ctx.systemPrompt.tools(() => [{ name: 'direct-tool', description: '', parameters: {} }])
+    expect((await ctx.systemPrompt.assemble()).tools).toHaveLength(1)
+
+    dispose()
+    expect((await ctx.systemPrompt.assemble()).tools).toHaveLength(0)
+  })
 })