> ## Documentation Index > Fetch the complete documentation index at: https://docs.decimal.ai/llms.txt > Use this file to discover all available pages before exploring further. # Glossary > Quick-reference definitions for every term used in DecimalAI. Alphabetical one-line definitions. For full explanations with diagrams, follow the **Learn More** links to the relevant concept page. *** | Term | Definition | Learn More | | -------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | -------------------------------------------------------------------- | | **Agent** | The system being versioned. Its configuration is captured as a manifest; traces, manifests, and datasets are all scoped to an agent. | [Execution Model](/concepts/execution-model) | | **agentversion** | The open spec (and PyPI package) for the manifest, diff, and compatibility-decision format DecimalAI builds on. | [Versioning & Compatibility](/concepts/versioning) | | **Baseline** | The manifest a regression check diffs against — typically the last manifest seen in production. | [Regression Check](/guides/regression-check) | | **Capability skill** | Skill type: teaches the base model an ability it genuinely lacks (parse a PDF layout, call an internal API, know an internal schema). Paired with a skill-scope. Formerly split as `model-gap` (public) / `proprietary` (private). | [Authoring Skills](/guides/authoring-skills) | | **Compat Status** | Convenience field on a trace: `keep`, `repair`, `replay`, or `drop`. (`compatible`/`incompatible` are accepted as legacy aliases that fold to `keep`/`drop`.) Authoritative source is the TraceCompat table. | [Versioning & Compatibility](/concepts/versioning) | | **Compatibility Report** | Analysis generated when a new manifest is registered, classifying every existing trace as keep/repair/replay/drop. | [Versioning & Compatibility](/concepts/versioning) | | **Compatibility Score** | 0.0–1.0 metric measuring how well a trace matches a manifest version. Category = `compatibility` on the EvalScore record. | [Evaluation](/concepts/evaluation) | | **Compatibility Verdict** | Per-trace outcome: keep, repair, replay, or drop. | [Versioning & Compatibility](/concepts/versioning) | | **Component** | A single versioned piece of a manifest: tool, model, prompt, skill, subagent, or output\_schema. | [Versioning & Compatibility](/concepts/versioning) | | **Component Verdict** | Per-component outcome when diffing old vs new manifests: COMPATIBLE, REPAIRABLE, INCOMPATIBLE, or MISSING. | [Versioning & Compatibility](/concepts/versioning#component-verdict) | | **Content Hash** | Per-component SHA-256 fingerprint. Changes when the component's definition changes. | [Versioning & Compatibility](/concepts/versioning) | | **Dataset** | Curated training data built from filtered, scored production traces. | [Skills & Data Pipeline](/concepts/skills-and-data) | | **Decision Engine** | System that combines quality + compatibility scores into a single keep/repair/replay/drop verdict per trace. | [Evaluation](/concepts/evaluation) | | **Degraded** | Parent trace status when some (not all) child traces errored. | [Multi-Agent Systems](/concepts/multi-agent) | | **Delegation** | Orchestrator → sub-agent task assignment. Control returns to orchestrator after sub-agent completes. | [Multi-Agent Systems](/concepts/multi-agent) | | **Detection Source** | How a manifest was created: `auto` (from traces) or `manual` (via SDK/API). | [Versioning & Compatibility](/concepts/versioning) | | **DPO** | Direct Preference Optimization. Dataset format with chosen/rejected pairs for preference training. | [Skills & Data Pipeline](/concepts/skills-and-data) | | **Drift** | When a sub-agent's actual config diverges from what the orchestrator's manifest expects. | [Multi-Agent Systems](/concepts/multi-agent) | | **Episode** | Compatibility engine synonym for "trace" — the same `RunTrace` record, just referred to in a compat context. | [Execution Model](/concepts/execution-model) | | **Eval Score** | Single evaluation result: name, score (0.0–1.0), passed (bool), source, category. | [Evaluation](/concepts/evaluation) | | **Eval Verdict** | Aggregate trace-level outcome: pass, fail, or review. Computed from all eval scores. | [Evaluation](/concepts/evaluation) | | **Evaluator** | A configured quality check — deterministic, LLM-as-judge, or custom. | [Evaluation](/concepts/evaluation) | | **Handoff** | Lateral transfer of control between peer agents. Unlike delegation, the original agent may not regain control. | [Multi-Agent Systems](/concepts/multi-agent) | | **Impact Report** | The structural, per-PR output of a regression check: each production trace marked HIGH / MEDIUM / LOW IMPACT by the manifest diff. The structural axis — distinct from the Compatibility Report (the data-lifecycle side). | [Regression Check](/guides/regression-check) | | **Impact Severity** | `HIGH` / `MEDIUM` / `LOW` — how structurally a manifest change touches a trace ("was this trace affected?"). Orthogonal to the keep/repair/replay/drop Compatibility Verdict. Not the same scale as component **Severity** (none/minor/moderate/major). | [Compatibility Policies](/guides/compatibility-policies) | | **Invocation Mode** | Who fires a skill: `model` (Automatic — the model triggers it from its description) or `user` (On-demand — zero context cost until explicitly called). `any` allows both. | [Authoring Skills](/guides/authoring-skills) | | **Lift** | The with-vs-without improvement: how much better an agent scores with a skill loaded than without it. Measured by skills ablation. | [Authoring Skills](/guides/authoring-skills) | | **LLM Call** | Single model invocation — rendered prompt, completion, tokens, latency, cost, tool calls. | [Execution Model](/concepts/execution-model) | | **Manifest** | Snapshot of an agent's full configuration (tools, models, prompts, skills, sub-agents) at a point in time. | [Versioning & Compatibility](/concepts/versioning) | | **Manifest Hash** | SHA-256 fingerprint of manifest structure. Same hash + same agent = idempotent. | [Versioning & Compatibility](/concepts/versioning) | | **Manifest Status** | Lifecycle state: `active`, `superseded`, or `draft`. | [Versioning & Compatibility](/concepts/versioning) | | **Orchestrator** | An agent that delegates to sub-agents. Inferred from manifest components or trace linkage — not explicitly declared. | [Multi-Agent Systems](/concepts/multi-agent) | | **Pack / Archetype** | A curated skill bundle that assembles a common agent role (support, coding, back-office ops), paired with a lean main prompt. The archetype is the role; the pack is the bundle that implements it. | [Assemble an Agent from Skills](/guides/agents-from-skills) | | **Parent Trace** | An orchestrator's trace record that child traces link back to via `parent_trace_id`. | [Multi-Agent Systems](/concepts/multi-agent) | | **Preference skill** | Skill type: the base model *can* do the task; the skill only steers the **form** to a chosen shape (PR-description format, commit convention, review checklist). Paired with a skill-scope; the `public` case is the legacy `convention`. | [Authoring Skills](/guides/authoring-skills) | | **Progressive Disclosure** | The skill-delivery pattern where cheap name+description rows are always in context and a skill's full body loads only on demand (e.g. via the `load_skill` tool) — so per-turn context cost stays flat as the registry grows. | [Assemble an Agent from Skills](/guides/agents-from-skills) | | **Quality Score** | Eval score measuring output quality (relevance, helpfulness, safety). Category = `quality` on EvalScore. | [Evaluation](/concepts/evaluation) | | **Regression Check** | The pre-deploy GitHub Action that diffs a candidate manifest against the baseline and posts an Impact Report comment on the PR. | [Regression Check](/guides/regression-check) | | **Repair** | Deterministic fix of a trace to match a new manifest. Zero LLM cost. | [Skills & Data Pipeline](/concepts/skills-and-data) | | **Replay** | Re-running a historical trace against the current agent to compare outputs. | [Skills & Data Pipeline](/concepts/skills-and-data) | | **Revert** | When the same manifest hash reappears — the old manifest is reactivated, the current one superseded. | [Versioning & Compatibility](/concepts/versioning) | | **Runs (`--runs`)** | Runner-level repetition: re-run the whole eval suite N times, uniformly, and average the per-case results by **mean** — the headline pass-rate's expected value doesn't depend on N, so more runs only narrow the error bars. Replaced per-case pass^k `trials` in skillevaluation 0.6.0 (ADR-0007). | [skillevaluation](/guides/skillevaluation) | | **Session** | Group of traces forming a multi-turn conversation. Linked by `session_id`. | [Execution Model](/concepts/execution-model) | | **Severity** | How impactful a component change is: none, minor, moderate, or major. | [Versioning & Compatibility](/concepts/versioning) | | **SFT** | Supervised Fine-Tuning. Dataset format with input→output pairs for imitation learning. | [Skills & Data Pipeline](/concepts/skills-and-data) | | **Skill** | Reusable instruction file (SKILL.md) that modifies agent behavior. Not a tool. | [Skills & Data Pipeline](/concepts/skills-and-data) | | **Skill Activation** | Record of which skills were loaded during a trace. | [Skills & Data Pipeline](/concepts/skills-and-data) | | **Skill Scope** | Second taxonomy axis: `public` (a standard the base may learn as models improve — RFC 9457, Conventional Commits) or `private` (internal house knowledge the base never absorbs). Only the `(capability, public)` pairing expires. | [Authoring Skills](/guides/authoring-skills) | | **Skill Type** | First taxonomy axis: `capability` (the base lacks the ability) or `preference` (the base can do it; the skill steers the form). Declared in frontmatter alongside skill-scope; together they predict the skill's lifespan and what its evals must show. Legacy `model-gap`/`proprietary`/`convention` still parse. | [Authoring Skills](/guides/authoring-skills) | | **skillevaluation** | The open spec (and PyPI package) for A/B benchmarking a skill — runs each test case with and without the skill, then reports the measured lift. | [skillevaluation](/guides/skillevaluation) | | **Skills Ablation** | Testing your agent with and without the skill loaded — the same eval suite run in both arms. How lift is measured at birth and how retirement is detected later. | [Authoring Skills](/guides/authoring-skills) | | **SkillScore** | The 0–100 composite that ranks skills in the registry — from benchmark lift, live eval pass rates, AI-judge quality, and cross-org adoption; never install counts alone. | [SkillScore](/guides/skillscore) | | **Source Type** | Where a trace came from: `production`, `playground`, `test`, or `replay`. | [Execution Model](/concepts/execution-model) | | **Span** | Timed segment within a trace (llm, tool, retriever, other). Nests via parent\_span\_id. | [Execution Model](/concepts/execution-model) | | **Sub-agent** | Agent receiving delegated work. Identified by `parent_trace_id` on its trace. | [Multi-Agent Systems](/concepts/multi-agent) | | **Surface** | Policy grouping for compatibility rules: tool\_registry, model\_runtime, prompt\_stack, skill\_registry, subagents, output\_contract. | [Versioning & Compatibility](/concepts/versioning#surface) | | **Trace** | A single, complete agent execution from input to output. The atomic unit of the platform. | [Execution Model](/concepts/execution-model) | | **Trajectory** | ML/RL term for a full (state, action, reward) sequence. DecimalAI traces are similar but use eval scores instead of explicit rewards. | [Execution Model](/concepts/execution-model) | | **Trigger Case** | An eval case marked `should_trigger: true/false` that grades whether a skill fires at the right times — not the quality of its output. | [skillevaluation](/guides/skillevaluation) | | **Trigger Health** | How reliably an Automatic skill fires at the right times: trigger recall and false-fire rate from its trigger cases, joined with production routing data (offered vs. actually selected). Shown on each registry skill's detail page. | [Community Registry](/guides/registry) | | **Turn** | A single interaction within a session. Each turn produces one trace. | [Execution Model](/concepts/execution-model) | | **Version Label** | Human-readable manifest identifier (v1, v2, v3). Auto-incremented — not semantic versioning. | [Versioning & Compatibility](/concepts/versioning) |