expect(api.logger.warn).toHaveBeenCalledWith(

expect.stringContaining("config.modelFallbackPolicy is deprecated"),

);

// #74587: deprecation warning must spell out the chain-resolution

// semantics so operators don't read it as a promise of runtime failover.

// The previous wording ("set config.modelFallback if you want a fallback

// model") cost real users hours of debug time before they hit the source

// and saw `getModelRef` only walks candidates once.

const warnCalls = (api.logger.warn as ReturnType<typeof vi.fn>).mock.calls;

const deprecationMessage = warnCalls

.map(([first]) => (typeof first === "string" ? first : ""))

.find((message) => message.includes("config.modelFallbackPolicy is deprecated"));

expect(deprecationMessage).toBeDefined();

// Positive: the warning describes chain-resolution last-resort behavior.

expect(deprecationMessage).toContain("chain-resolution");

expect(deprecationMessage).toContain("last-resort");

// Negative: the warning explicitly disclaims runtime failover, since

// that's the wrong mental model the previous wording invited.

expect(deprecationMessage).toMatch(/NOT a runtime failover/i);

});

it("does not use a built-in fallback model even when default-remote is configured", async () => {

let config = normalizePluginConfig(api.pluginConfig);

const warnDeprecatedModelFallbackPolicy = (pluginConfig: unknown) => {

if (hasDeprecatedModelFallbackPolicy(pluginConfig)) {

// Wording matters here: the previous text ("set config.modelFallback

// explicitly if you want a fallback model") read naturally as runtime

// failover (model A errors → switch to model B), but `getModelRef`

// only consults `modelFallback` as the *last candidate* in the

// resolution chain after `config.model`, the current run's model,

// and the agent's configured default have all resolved to nothing.

// Surface the chain-resolution semantics directly so operators

// don't waste debug cycles assuming runtime failover (#74587).

api.logger.warn?.(

"active-memory: config.modelFallbackPolicy is deprecated and no longer changes runtime behavior; set config.modelFallback explicitly if you want a fallback model",

"active-memory: config.modelFallbackPolicy is deprecated and no longer changes runtime behavior. " +

"config.modelFallback is a chain-resolution last-resort (consulted only when config.model, " +

"the current run's model, and the agent's configured default all resolve to nothing) — " +

"it is NOT a runtime failover that substitutes a different model when the resolved model errors out.",

);

}

};