Proposed specificationSource-located exemplarH1 H3

Inheritance and polymorphic routing

Specialize related harnesses.

JOIN POINTharness_specialization_via_subtypeRECORD STATUSCandidate · v0.1.0

UML class view

The proposed contract drawn as participant roles, received calls, and numbered dependencies.

Object interactions

The same roles and calls as a class collaboration and a numbered message sequence.

Object interaction diagram for Inheritance and polymorphic routing, showing role collaboration and a numbered message sequence — FIG. E01 / OBJECT INTERACTIONS
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Pointcut

Where the mechanism applies. All four dimensions belong to the proposed match, not just its vocabulary.

Context: Harness variants share a base abstraction.
Trigger: A base-typed slot dispatches to a concrete implementation.
Structure: Base interface, overridden behavior, subtype registry, and invariant clauses.
Effect: Any accepted subtype honors the base contract at the dispatch boundary.

Protected contract

The obligation that clients, operators, and auditors should be able to rely on.

Requires: The base interface declares substitutable behavior.
Ensures: Runtime dispatch reaches the intended specialized implementation.
Invariant: Subtype overrides do not narrow required capabilities or violate base obligations.
Violation: Unsupported subtype behavior raises or is excluded from the slot.

Negative control

A class hierarchy with no harness dispatch does not count.

Variation & lifecycle

The hot spot is admitted only where the protected semantics survive.

Permitted variation

Class inheritance, interfaces, protocols, and plugin subclasses.

Test obligation

Test substitutability, dispatch, override errors, and invalid subtype.

Evolution question

Did inheritance replace ad hoc branching or move toward composition?

Prompt + code design

An illustrative prompt and a small design sketch for the proposed contract. Names and APIs are invented; this is not a repository excerpt.

PROMPT SKETCH

Specialize the base harness only through a substitutable contract. Dispatch to the intended subtype at the declared boundary, and keep base behavior legal for every override.

CODE DESIGN / PYTHON

class Harness(Protocol):
    def step(self, state: State) -> State: ...

class ToolHarness:
    def step(self, state):
        return state.with_action(self.tools.choose(state))

class WorkflowHarness:
    def step(self, state):
        return state.with_workflow(self.workflows.advance(state))

def run(harness: Harness, state):
    return harness.step(state)

Illustrative design sketch. Inheritance is only a pattern when the base contract survives substitution. This example is a teaching aid, not implementation evidence or a conformance claim.

Detection & matching

The frozen rule that retrieves this record, the canonical source exemplar, and the control that should stay unmatched.

Join point: harness_specialization_via_subtype
Source locator: See the source record.
Lexical cue: (?i)\bclass\s+\w*Agent\w*|\bextends\s+\w*Agent\w*|\binherits?\s+from\s+\w*Agent\w*Frozen expression, v0.1.0. A match is a retrieval cue, not a confirmed implementation.
Aliases: None
Canonical exemplar: crewAIInc/crewAIlib/crewai/src/crewai/agent/core.py:223Support: lib/crewai/tests/test_crew.py:4770
Negative control: A class hierarchy with no harness dispatch does not count.

Scope-anchored review. pohe-agent analyze <repo> --pattern E01 anchors the cue to its enclosing declaration and checks a separate operational signature for all four pointcut dimensions. Missing roles and negative-control risks remain visible; a structural match is not E2/E3. Calibration report ↗

Repository files

Up to five public files retrieved by the frozen cue and pinned to the audited commit. A match is a place to inspect, not a confirmed implementation.

01crewAIInc/crewAIlib/crewai/src/crewai/agent/core.py:223CANONICAL SOURCE 02affaan-m/ECCsrc/llm/tools/executor.py:123RETRIEVAL CUE 03agno-agi/agnolibs/agno/agno/agent/agent.py:82RETRIEVAL CUE 04anomalyco/opencodepackages/cli/src/acp/agent.ts:59RETRIEVAL CUE 05browser-use/browser-usebrowser_use/agent/cloud_events.py:18RETRIEVAL CUE

Evidence & provenance

Each layer answers a different question. Do not substitute retrieval for review.

Source-located exemplar

A concrete source anchor is available for this proposed record. It is one exemplar, not evidence that all repositories—or every contract field—conform.

Review boundary: this candidate and its specification come from an AI-assisted study. Independent human validation remains open.

ANY-EVIDENCE FAMILY COVERAGE33/36

91.7% of repository families in the frozen panel have at least one current cue, historical cue, or canonical source layer. This is not confirmed prevalence.

Current lexical-cue repositories: 37 / 41

Canonical source anchorcrewAIInc/crewAI 7abc196a176alib/crewai/src/crewai/agent/core.py:223

Supporting surfacelib/crewai/tests/test_crew.py:4770

Concrete Agent specializes BaseAgent.

Exploratory retrieval cue Regex / v0.1.0

(?i)\bclass\s+\w*Agent\w*|\bextends\s+\w*Agent\w*|\binherits?\s+from\s+\w*Agent\w*

This expression is a discovery instrument only. A match is a retrieval cue—not a confirmed implementation, pointcut match, or contract proof.