Proposed specificationSource-located exemplarH1

Middleware-pipeline loop

Layer behavior around model/tool calls.

JOIN POINTmodel_or_tool_call_boundaryRECORD 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 Middleware-pipeline loop, showing role collaboration and a numbered message sequence — FIG. P04 / OBJECT INTERACTIONS
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Pointcut

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

Context: A harness surrounds model or tool invocation with extensible behavior.
Trigger: A call enters or leaves the runtime boundary.
Structure: Ordered middleware entries with a continuation or short-circuit result.
Effect: Logging, policy, retry, or context behavior runs in declared order.

Protected contract

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

Requires: The boundary exposes a composable continuation contract.
Ensures: Middleware executes in deterministic order and the final result reaches the loop.
Invariant: A middleware does not silently bypass required downstream layers.
Violation: Short circuits and exceptions unwind deterministically with one terminal result.

Negative control

A hard-coded helper call is not a middleware pipeline.

Variation & lifecycle

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

Permitted variation

Registration order, retry, redaction, tracing, and policy middleware.

Test obligation

Test order, short circuit, exception, and repeated side-effect calls.

Evolution question

Did provider-specific logic move into policy or middleware layers?

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

Apply model and tool calls through an ordered middleware chain. Each layer may inspect, annotate, redact, or reject a call, but the final handler must see the composed result exactly once.

CODE DESIGN / PYTHON

def compose(layers, handler):
    call = handler
    for layer in reversed(layers):
        call = layer(call)
    return call

pipeline = compose(
    [trace_calls, redact_secrets, enforce_budget, retry_transient],
    invoke_model,
)
result = pipeline(request)

Illustrative design sketch. Order is part of the contract; record the resolved chain with the result. 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: model_or_tool_call_boundary
Source locator: Barbaste et al., §6.2, p. 14 (Mistral Vibe, “Middleware-Pipeline Loop”); Table 11, p. 52; source label
Lexical cue: (?i)\bmiddleware\b|\badd_middleware\b|\bon_[a-z_]+\bFrozen expression, v0.1.0. A match is a retrieval cue, not a confirmed implementation.
Aliases: None
Canonical exemplar: microsoft/agent-frameworkpython/packages/core/agent_framework/_middleware.py:860Support: python/packages/core/tests/core/test_middleware_context_result.py:46
Negative control: A hard-coded helper call is not a middleware pipeline.

Scope-anchored review. pohe-agent analyze <repo> --pattern P04 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.

01microsoft/agent-frameworkpython/packages/core/agent_framework/_middleware.py:860CANONICAL SOURCE 02aaif-goose/goosecrates/goose/src/acp/provider.rs:1227RETRIEVAL CUE 03agno-agi/agnolibs/agno/agno/db/singlestore/singlestore.py:567RETRIEVAL CUE 04Aider-AI/aideraider/analytics.py:105RETRIEVAL CUE 05anomalyco/opencodepackages/ai/example/tutorial.ts:225RETRIEVAL 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 COVERAGE34/36

94.4% 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: 38 / 41

Canonical source anchormicrosoft/agent-framework 71e56792f5dbpython/packages/core/agent_framework/_middleware.py:860

Supporting surfacepython/packages/core/tests/core/test_middleware_context_result.py:46

Typed agent middleware pipeline.

Exploratory retrieval cue Regex / v0.1.0

(?i)\bmiddleware\b|\badd_middleware\b|\bon_[a-z_]+\b

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