Interface: MiddlewareDecision

Defined in: src/core/agent/middleware/types.ts:325

One row per middleware decision, committed to scope.middlewareDecisions.

Every decision files a row, including the pass-throughs. A chain that only recorded its refusals would leave you unable to tell "the middleware looked and was fine with it" apart from "the middleware never ran" — and those are different facts about a run.

Properties

after?

readonly optional after?: unknown

Defined in: src/core/agent/middleware/types.ts:373

The value after this middleware. Present only when changed.

at

readonly at: "tool" | "message"

Defined in: src/core/agent/middleware/types.ts:339

Which chain this row came from. The older spelling — see moment.

before?

readonly optional before?: unknown

Defined in: src/core/agent/middleware/types.ts:371

The value before this middleware. Present only when changed.

At 'after-tool' this is the tool's REAL result — including on a refusal, because the side effect happened and a record that dropped it would be a record that lies. It is not the only copy: by design agentfootprint.stream.tool_end reports the same real result. If it must not survive in a record, name it in the agent's redact (Agent.create({ redact }) — conversationRedaction() names middlewareDecisions and result): the row survives, the value does not.

changed

readonly changed: boolean

Defined in: src/core/agent/middleware/types.ts:357

True when this row changed the value the chain carries forward.

A refusal at 'before-tool' leaves nothing to change — the call does not happen. A refusal at 'after-tool' DOES change something: the tool ran, and the model is handed the reason instead of what came back. Those rows carry changed: true with the real result in before.

changedKeys?

readonly optional changedKeys?: readonly string[]

Defined in: src/core/agent/middleware/types.ts:392

The NAMES of the arguments this before-tool rewrite changed (honesty layer 2) — filed only on an agent whose inputs layer is armed, for a call whose tool declares argument rules; names only, never values (the row already carries before and after). The answer's standing reads a rewrite of a RULED argument with no declared origin as assumed.

componentId?

readonly optional componentId?: string

Defined in: src/core/agent/middleware/types.ts:379

The registered component that COLLECTED this decision (9.24.0). Present only on the resume-side rows of an ask that carried one — the trace then says which surface the person answered through. Never inferred.

from?

readonly optional from?: Readonly<Record<string, "person" | "default" | "app">>

Defined in: src/core/agent/middleware/types.ts:384

The middleware's own declaration of where the rewritten values came from (allow(args, why, { from })) — present only when it declared one.

iteration

readonly iteration: number

Defined in: src/core/agent/middleware/types.ts:347

ReAct iteration. 0 for the 'input' phase, which runs before iter 1.

middleware

readonly middleware: string

Defined in: src/core/agent/middleware/types.ts:327

The middleware's name.

moment

readonly moment: "input" | "output" | "before-tool" | "after-tool" | "window"

Defined in: src/core/agent/middleware/types.ts:337

WHERE IN THE LOOP this decision happened — the same five words .act() is keyed on, so a row and the door that filed it are read in one vocabulary.

at and phase below say the same thing in the spelling 7.18 shipped with. They are committed state and they are not going anywhere; this is the newer word for the same fact, and the one to narrow on.