steve
76ecf0e49e
Phase 6: skill.New constructor satisfying the agent.Skill contract; instruction-only skills; ordered additive composition; skill/clock (injectable-clock time tools) and skill/calc (recursive-descent arithmetic evaluator) as ready-made examples with full test suites incl. an agent-loop round trip. ADR-0013; README skills section + matrix synced. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
38 lines
1.8 KiB
Markdown
38 lines
1.8 KiB
Markdown
# ADR-0013: Skill model — additive instruction+tool bundles
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**Status:** Accepted — 2026-06-10
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## Context
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mort's "skills" are reusable capabilities (a prompt fragment plus tools)
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attached to different agents at runtime. majordomo needs the same shape
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without mort specifics: attachable to any agent, on demand, composing
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additively and predictably.
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## Decision
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- The **contract** is the three-method `agent.Skill` interface (Name /
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Instructions / Tools). It lives in package agent — the consumer of the
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contract — so skill→agent and agent→skill never both happen (no import
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cycle, and third parties can satisfy it without importing package skill).
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- Package **skill** is the standard constructor: `skill.New(name,
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WithInstructions(...), WithTools(...)/WithToolbox(...))`. Instruction-only
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skills (nil toolbox) are legal — agent treats Tools()==nil as "no tools".
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- **Composition is additive and ordered:** instructions append to the
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agent's system prompt in attachment order, separated by blank lines;
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skill tools join the merged toolset with the same loud duplicate-name
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policy as toolboxes (ADR-0012). No hooks, no resources, no lifecycle —
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none of mort's skills need them, and out-of-scope discipline says don't
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build for hypotheticals (they'd be an additive interface upgrade later).
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- Two ready-made example skills ship as subpackages and double as the
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pattern reference: `skill/clock` (time awareness; injectable clock) and
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`skill/calc` (exact arithmetic via a hand-rolled recursive-descent
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evaluator — no eval, no dependencies).
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## Consequences
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- A skill instance is reusable across agents simultaneously (it is
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read-only after construction).
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- mort's skill registry maps onto plain values: build `*skill.Skill`s,
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attach per agent at invocation time.
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