diff --git a/agents-api.php b/agents-api.php
index 6d74ef3..7ed4196 100644
--- a/agents-api.php
+++ b/agents-api.php
@@ -76,6 +76,8 @@
 require_once AGENTS_API_PATH . 'src/Auth/register-agent-access-abilities.php';
 require_once AGENTS_API_PATH . 'src/Runtime/functions-input-normalization.php';
 require_once AGENTS_API_PATH . 'src/Runtime/functions-sse-response.php';
+require_once AGENTS_API_PATH . 'src/Runtime/class-wp-agent-runtime-profile.php';
+require_once AGENTS_API_PATH . 'src/Runtime/interface-wp-agent-runtime-profile-provider.php';
 require_once AGENTS_API_PATH . 'src/Context/class-wp-agent-context-injection-policy.php';
 require_once AGENTS_API_PATH . 'src/Context/class-wp-agent-memory-layer.php';
 require_once AGENTS_API_PATH . 'src/Context/class-wp-agent-memory-registry.php';
@@ -140,6 +142,8 @@
 require_once AGENTS_API_PATH . 'src/Tools/class-wp-agent-default-tool-tier-resolver.php';
 require_once AGENTS_API_PATH . 'src/Tools/register-agent-ability-meta-abilities.php';
 require_once AGENTS_API_PATH . 'src/Runtime/class-wp-agent-conversation-request.php';
+require_once AGENTS_API_PATH . 'src/Runtime/class-wp-agent-runtime-profile-resolver.php';
+require_once AGENTS_API_PATH . 'src/Runtime/functions-agent-runtime-profile.php';
 require_once AGENTS_API_PATH . 'src/Runtime/class-wp-agent-conversation-runner.php';
 require_once AGENTS_API_PATH . 'src/Runtime/class-wp-agent-provider-turn-request.php';
 require_once AGENTS_API_PATH . 'src/Runtime/class-wp-agent-provider-turn-result.php';
diff --git a/composer.json b/composer.json
index 475a8f4..9d16a9d 100644
--- a/composer.json
+++ b/composer.json
@@ -34,6 +34,7 @@
       "php tests/package-adoption-orchestration-smoke.php",
       "php tests/execution-principal-smoke.php",
       "php tests/effective-agent-resolver-smoke.php",
+      "php tests/runtime-profile-smoke.php",
       "php tests/caller-context-smoke.php",
       "php tests/authorization-smoke.php",
       "php tests/autonomous-capability-ceiling-smoke.php",
diff --git a/src/Runtime/class-wp-agent-runtime-profile-resolver.php b/src/Runtime/class-wp-agent-runtime-profile-resolver.php
new file mode 100644
index 0000000..5caf008
--- /dev/null
+++ b/src/Runtime/class-wp-agent-runtime-profile-resolver.php
@@ -0,0 +1,330 @@
+<?php
+/**
+ * Agent runtime profile resolver.
+ *
+ * @package AgentsAPI
+ */
+
+namespace AgentsAPI\AI;
+
+use AgentsAPI\Core\Identity\WP_Agent_Materialized_Identity;
+
+defined( 'ABSPATH' ) || exit;
+
+/**
+ * Resolves an auditable provider/model binding for an agent.
+ */
+final class WP_Agent_Runtime_Profile_Resolver {
+
+	/**
+	 * Resolve an agent runtime profile.
+	 *
+	 * Precedence, per field: explicit context override > runtime_overrides > host
+	 * providers > config arrays. Provider and model are resolved independently so
+	 * a higher-priority source can provide one field while another source provides
+	 * the other. Empty strings are valid resolved field values.
+	 *
+	 * @param \WP_Agent           $agent   Registered agent definition.
+	 * @param array<string,mixed> $context Runtime resolution context.
+	 * @return WP_Agent_Runtime_Profile|null Resolved profile, or null when no binding exists.
+	 */
+	public function resolve( \WP_Agent $agent, array $context = array() ): ?WP_Agent_Runtime_Profile {
+		$provider_id = null;
+		$model_id    = null;
+		$provenance  = array(
+			'config_sources' => array(),
+		);
+		$identity    = $this->identity_payload( $context['identity'] ?? null );
+
+		$this->apply_context_overrides( $context, $provider_id, $model_id, $provenance );
+		$this->apply_runtime_overrides( $agent, $context, $provider_id, $model_id, $provenance );
+		$this->apply_host_providers( $agent, $context, $provider_id, $model_id, $identity, $provenance );
+		$this->apply_config_sources( $agent, $context, $provider_id, $model_id, $provenance );
+
+		if ( null === $provider_id && null === $model_id && null === $identity ) {
+			return $this->apply_final_filter( null, $agent, $context );
+		}
+
+		$profile = new WP_Agent_Runtime_Profile(
+			$agent->get_slug(),
+			(string) ( $provider_id ?? '' ),
+			(string) ( $model_id ?? '' ),
+			$identity,
+			$provenance
+		);
+
+		return $this->apply_final_filter( $profile, $agent, $context );
+	}
+
+	/**
+	 * @param array<string,mixed>      $context    Runtime context.
+	 * @param string|null             $provider_id Resolved provider id.
+	 * @param string|null             $model_id    Resolved model id.
+	 * @param array<string,mixed>     $provenance  Field provenance.
+	 */
+	private function apply_context_overrides( array $context, ?string &$provider_id, ?string &$model_id, array &$provenance ): void {
+		$model = is_array( $context['model'] ?? null ) ? $context['model'] : array();
+
+		if ( null === $provider_id && array_key_exists( 'provider_id', $context ) && is_scalar( $context['provider_id'] ) ) {
+			$provider_id               = (string) $context['provider_id'];
+			$provenance['provider_id'] = array(
+				'source' => 'context',
+				'path'   => 'provider_id',
+			);
+		} elseif ( null === $provider_id && array_key_exists( 'provider_id', $model ) && is_scalar( $model['provider_id'] ) ) {
+			$provider_id               = (string) $model['provider_id'];
+			$provenance['provider_id'] = array(
+				'source' => 'context',
+				'path'   => 'model.provider_id',
+			);
+		}
+
+		if ( null === $model_id && array_key_exists( 'model_id', $context ) && is_scalar( $context['model_id'] ) ) {
+			$model_id               = (string) $context['model_id'];
+			$provenance['model_id'] = array(
+				'source' => 'context',
+				'path'   => 'model_id',
+			);
+		} elseif ( null === $model_id && array_key_exists( 'model_id', $model ) && is_scalar( $model['model_id'] ) ) {
+			$model_id               = (string) $model['model_id'];
+			$provenance['model_id'] = array(
+				'source' => 'context',
+				'path'   => 'model.model_id',
+			);
+		}
+	}
+
+	/**
+	 * @param \WP_Agent               $agent       Agent definition.
+	 * @param array<string,mixed>     $context     Runtime context.
+	 * @param string|null             $provider_id Resolved provider id.
+	 * @param string|null             $model_id    Resolved model id.
+	 * @param array<string,mixed>     $provenance  Field provenance.
+	 */
+	private function apply_runtime_overrides( \WP_Agent $agent, array $context, ?string &$provider_id, ?string &$model_id, array &$provenance ): void {
+		$overrides = $context['runtime_overrides'] ?? null;
+		if ( ! $overrides instanceof \WP_Agent_Runtime_Overrides ) {
+			$overrides = $agent->runtime_overrides();
+		}
+
+		if ( null === $provider_id && null !== $overrides->provider_id() ) {
+			$provider_id               = $overrides->provider_id();
+			$provenance['provider_id'] = array(
+				'source' => 'runtime_overrides',
+				'path'   => 'provider_id',
+			);
+		}
+
+		if ( null === $model_id && null !== $overrides->model_id() ) {
+			$model_id               = $overrides->model_id();
+			$provenance['model_id'] = array(
+				'source' => 'runtime_overrides',
+				'path'   => 'model_id',
+			);
+		}
+	}
+
+	/**
+	 * @param \WP_Agent                       $agent       Agent definition.
+	 * @param array<string,mixed>             $context     Runtime context.
+	 * @param string|null                     $provider_id Resolved provider id.
+	 * @param string|null                     $model_id    Resolved model id.
+	 * @param array<string,mixed>|null        $identity    Identity payload.
+	 * @param array<string,mixed>             $provenance  Field provenance.
+	 */
+	private function apply_host_providers( \WP_Agent $agent, array $context, ?string &$provider_id, ?string &$model_id, ?array &$identity, array &$provenance ): void {
+		foreach ( $this->get_profile_providers( $agent, $context ) as $index => $provider ) {
+			$profile = $provider->resolve_agent_runtime_profile( $agent, $context );
+			if ( ! $profile instanceof WP_Agent_Runtime_Profile ) {
+				continue;
+			}
+
+			$host_provenance = $profile->provenance();
+			if ( null === $provider_id ) {
+				$provider_id               = $profile->provider_id();
+				$provenance['provider_id'] = is_array( $host_provenance['provider_id'] ?? null ) ? $host_provenance['provider_id'] : array(
+					'source' => 'runtime_profile_provider',
+					'path'   => 'runtime_profile_providers.' . $index . '.provider_id',
+				);
+			}
+
+			if ( null === $model_id ) {
+				$model_id               = $profile->model_id();
+				$provenance['model_id'] = is_array( $host_provenance['model_id'] ?? null ) ? $host_provenance['model_id'] : array(
+					'source' => 'runtime_profile_provider',
+					'path'   => 'runtime_profile_providers.' . $index . '.model_id',
+				);
+			}
+
+			if ( null === $identity && null !== $profile->identity() ) {
+				$identity = $profile->identity();
+			}
+
+			$this->append_config_source( $provenance, 'runtime_profile_provider', 'runtime_profile_providers.' . $index );
+			break;
+		}
+	}
+
+	/**
+	 * @param \WP_Agent               $agent       Agent definition.
+	 * @param array<string,mixed>     $context     Runtime context.
+	 * @param string|null             $provider_id Resolved provider id.
+	 * @param string|null             $model_id    Resolved model id.
+	 * @param array<string,mixed>     $provenance  Field provenance.
+	 */
+	private function apply_config_sources( \WP_Agent $agent, array $context, ?string &$provider_id, ?string &$model_id, array &$provenance ): void {
+		$mode    = isset( $context['mode'] ) && is_scalar( $context['mode'] ) ? trim( (string) $context['mode'] ) : '';
+		$sources = array();
+
+		if ( is_array( $context['agent_config'] ?? null ) ) {
+			$sources[] = array( 'source' => 'context.agent_config', 'config' => $this->string_keyed_array( $context['agent_config'] ) );
+		}
+
+		$identity = $context['identity'] ?? null;
+		if ( $identity instanceof WP_Agent_Materialized_Identity ) {
+			$sources[] = array( 'source' => 'identity.config', 'config' => $this->string_keyed_array( $identity->config ) );
+		}
+
+		$sources[] = array( 'source' => 'agent.default_config', 'config' => $this->string_keyed_array( $agent->get_default_config() ) );
+
+		foreach ( $sources as $source ) {
+			$config = $source['config'];
+			if ( array() === $config ) {
+				continue;
+			}
+
+			$this->append_config_source( $provenance, $source['source'], '' );
+
+			$mode_models = is_array( $config['mode_models'] ?? null ) ? $config['mode_models'] : array();
+			if ( '' !== $mode && is_array( $mode_models[ $mode ] ?? null ) ) {
+				$mode_config = $this->string_keyed_array( $mode_models[ $mode ] );
+				$this->apply_config_field( $mode_config, 'provider_id', 'provider', 'mode_models.' . $mode, (string) $source['source'], $provider_id, $provenance );
+				$this->apply_config_field( $mode_config, 'model_id', 'model', 'mode_models.' . $mode, (string) $source['source'], $model_id, $provenance );
+			}
+
+			$this->apply_config_field( $config, 'default_provider_id', 'default_provider', '', (string) $source['source'], $provider_id, $provenance );
+			$this->apply_config_field( $config, 'default_model_id', 'default_model', '', (string) $source['source'], $model_id, $provenance );
+
+			if ( null !== $provider_id && null !== $model_id ) {
+				break;
+			}
+		}
+	}
+
+	/**
+	 * @param array<string,mixed> $config      Config map.
+	 * @param string              $primary_key Preferred key.
+	 * @param string              $fallback_key Fallback key.
+	 * @param string              $prefix      Provenance path prefix.
+	 * @param string              $source      Provenance source.
+	 * @param string|null         $target      Resolved target field.
+	 * @param array<string,mixed> $provenance  Field provenance.
+	 */
+	private function apply_config_field( array $config, string $primary_key, string $fallback_key, string $prefix, string $source, ?string &$target, array &$provenance ): void {
+		if ( null !== $target ) {
+			return;
+		}
+
+		$key   = null;
+		$value = null;
+		if ( array_key_exists( $primary_key, $config ) && is_scalar( $config[ $primary_key ] ) ) {
+			$key = $primary_key;
+			$value = $config[ $primary_key ];
+		} elseif ( array_key_exists( $fallback_key, $config ) && is_scalar( $config[ $fallback_key ] ) ) {
+			$key   = $fallback_key;
+			$value = $config[ $fallback_key ];
+		}
+
+		if ( null === $key ) {
+			return;
+		}
+
+		$field  = str_contains( $primary_key, 'provider' ) ? 'provider_id' : 'model_id';
+		$target = (string) $value;
+
+		$provenance[ $field ] = array(
+			'source' => $source,
+			'path'   => '' === $prefix ? $key : $prefix . '.' . $key,
+		);
+	}
+
+	/**
+	 * @param \WP_Agent           $agent   Agent definition.
+	 * @param array<string,mixed> $context Runtime context.
+	 * @return WP_Agent_Runtime_Profile_Provider[] Providers.
+	 */
+	private function get_profile_providers( \WP_Agent $agent, array $context ): array {
+		$providers = array();
+		if ( is_array( $context['runtime_profile_providers'] ?? null ) ) {
+			$providers = array_merge( $providers, $context['runtime_profile_providers'] );
+		}
+
+		if ( function_exists( 'apply_filters' ) ) {
+			$providers = apply_filters( 'agents_api_runtime_profile_providers', $providers, $agent, $context );
+		}
+
+		return array_values(
+			array_filter(
+				is_array( $providers ) ? $providers : array(),
+				static fn( $provider ): bool => $provider instanceof WP_Agent_Runtime_Profile_Provider
+			)
+		);
+	}
+
+	/**
+	 * @param mixed $identity Raw identity context.
+	 * @return array<string,mixed>|null Identity payload.
+	 */
+	private function identity_payload( $identity ): ?array {
+		if ( $identity instanceof WP_Agent_Materialized_Identity ) {
+			return $identity->to_array();
+		}
+
+		return is_array( $identity ) ? $this->string_keyed_array( $identity ) : null;
+	}
+
+	/**
+	 * @param array<string,mixed> $provenance Field provenance.
+	 * @param string              $source     Source label.
+	 * @param string              $path       Source path.
+	 */
+	private function append_config_source( array &$provenance, string $source, string $path ): void {
+		if ( ! is_array( $provenance['config_sources'] ?? null ) ) {
+			$provenance['config_sources'] = array();
+		}
+
+		$provenance['config_sources'][] = array(
+			'source' => $source,
+			'path'   => $path,
+		);
+	}
+
+	/**
+	 * @param array<mixed> $value Raw map.
+	 * @return array<string,mixed>
+	 */
+	private function string_keyed_array( array $value ): array {
+		$result = array();
+		foreach ( $value as $key => $item ) {
+			if ( is_string( $key ) ) {
+				$result[ $key ] = $item;
+			}
+		}
+
+		return $result;
+	}
+
+	/**
+	 * @param WP_Agent_Runtime_Profile|null $profile Profile before final filter.
+	 * @param \WP_Agent                     $agent   Agent definition.
+	 * @param array<string,mixed>           $context Runtime context.
+	 * @return WP_Agent_Runtime_Profile|null Filtered profile.
+	 */
+	private function apply_final_filter( ?WP_Agent_Runtime_Profile $profile, \WP_Agent $agent, array $context ): ?WP_Agent_Runtime_Profile {
+		if ( function_exists( 'apply_filters' ) ) {
+			$profile = apply_filters( 'agents_api_resolved_agent_runtime_profile', $profile, $agent, $context );
+		}
+
+		return $profile instanceof WP_Agent_Runtime_Profile ? $profile : null;
+	}
+}
diff --git a/src/Runtime/class-wp-agent-runtime-profile.php b/src/Runtime/class-wp-agent-runtime-profile.php
new file mode 100644
index 0000000..59aa01c
--- /dev/null
+++ b/src/Runtime/class-wp-agent-runtime-profile.php
@@ -0,0 +1,68 @@
+<?php
+/**
+ * Agent runtime profile value object.
+ *
+ * @package AgentsAPI
+ */
+
+namespace AgentsAPI\AI;
+
+defined( 'ABSPATH' ) || exit;
+
+/**
+ * Immutable provider/model binding resolved for an agent at runtime.
+ */
+final class WP_Agent_Runtime_Profile {
+
+	/**
+	 * @param array<string,mixed>|null $identity   Optional materialized identity payload.
+	 * @param array<string,mixed>      $provenance Field-level provenance metadata.
+	 */
+	public function __construct(
+		private readonly string $agent_slug,
+		private readonly string $provider_id,
+		private readonly string $model_id,
+		private readonly ?array $identity = null,
+		private readonly array $provenance = array()
+	) {}
+
+	/** @return string Agent slug. */
+	public function agent_slug(): string {
+		return $this->agent_slug;
+	}
+
+	/** @return string Provider identifier. */
+	public function provider_id(): string {
+		return $this->provider_id;
+	}
+
+	/** @return string Model identifier. */
+	public function model_id(): string {
+		return $this->model_id;
+	}
+
+	/** @return array<string,mixed>|null Optional materialized identity payload. */
+	public function identity(): ?array {
+		return $this->identity;
+	}
+
+	/** @return array<string,mixed> Field-level provenance metadata. */
+	public function provenance(): array {
+		return $this->provenance;
+	}
+
+	/**
+	 * Return a stable array shape for diagnostics and handoff to callers.
+	 *
+	 * @return array<string,mixed>
+	 */
+	public function to_array(): array {
+		return array(
+			'agent_slug'  => $this->agent_slug,
+			'provider_id' => $this->provider_id,
+			'model_id'    => $this->model_id,
+			'identity'    => $this->identity,
+			'provenance'  => $this->provenance,
+		);
+	}
+}
diff --git a/src/Runtime/functions-agent-runtime-profile.php b/src/Runtime/functions-agent-runtime-profile.php
new file mode 100644
index 0000000..7d61d0b
--- /dev/null
+++ b/src/Runtime/functions-agent-runtime-profile.php
@@ -0,0 +1,30 @@
+<?php
+/**
+ * Agent runtime profile helper.
+ *
+ * @package AgentsAPI
+ */
+
+defined( 'ABSPATH' ) || exit;
+
+if ( ! function_exists( 'wp_resolve_agent_runtime_profile' ) ) {
+	/**
+	 * Resolve the runtime provider/model profile for an agent.
+	 *
+	 * @param WP_Agent|string      $agent   Agent instance or registered agent slug.
+	 * @param array<string,mixed> $context Runtime resolution context.
+	 * @return \AgentsAPI\AI\WP_Agent_Runtime_Profile|null Runtime profile, or null when no binding exists.
+	 */
+	function wp_resolve_agent_runtime_profile( $agent, array $context = array() ): ?\AgentsAPI\AI\WP_Agent_Runtime_Profile {
+		if ( is_string( $agent ) ) {
+			$agent = function_exists( 'wp_get_agent' ) ? wp_get_agent( $agent ) : null;
+		}
+
+		if ( ! $agent instanceof WP_Agent ) {
+			return null;
+		}
+
+		$resolver = new \AgentsAPI\AI\WP_Agent_Runtime_Profile_Resolver();
+		return $resolver->resolve( $agent, $context );
+	}
+}
diff --git a/src/Runtime/interface-wp-agent-runtime-profile-provider.php b/src/Runtime/interface-wp-agent-runtime-profile-provider.php
new file mode 100644
index 0000000..a02fff3
--- /dev/null
+++ b/src/Runtime/interface-wp-agent-runtime-profile-provider.php
@@ -0,0 +1,25 @@
+<?php
+/**
+ * Host-supplied agent runtime profile provider contract.
+ *
+ * @package AgentsAPI
+ */
+
+namespace AgentsAPI\AI;
+
+defined( 'ABSPATH' ) || exit;
+
+/**
+ * Allows hosts to provide a generic runtime provider/model binding for an agent.
+ */
+interface WP_Agent_Runtime_Profile_Provider {
+
+	/**
+	 * Resolve a runtime profile for the given agent and request context.
+	 *
+	 * @param \WP_Agent           $agent   Registered agent definition.
+	 * @param array<string,mixed> $context Runtime resolution context.
+	 * @return WP_Agent_Runtime_Profile|null Runtime profile, or null when this provider has no binding.
+	 */
+	public function resolve_agent_runtime_profile( \WP_Agent $agent, array $context ): ?WP_Agent_Runtime_Profile;
+}
diff --git a/tests/runtime-profile-smoke.php b/tests/runtime-profile-smoke.php
new file mode 100644
index 0000000..3097d79
--- /dev/null
+++ b/tests/runtime-profile-smoke.php
@@ -0,0 +1,114 @@
+<?php
+/**
+ * Pure-PHP smoke test for agent runtime profile resolution.
+ *
+ * Run with: php tests/runtime-profile-smoke.php
+ *
+ * @package AgentsAPI\Tests
+ */
+
+use AgentsAPI\AI\WP_Agent_Runtime_Profile;
+use AgentsAPI\AI\WP_Agent_Runtime_Profile_Provider;
+
+if ( ! defined( 'ABSPATH' ) ) {
+	define( 'ABSPATH', __DIR__ . '/' );
+}
+
+$failures = array();
+$passes   = 0;
+
+echo "agents-api-runtime-profile-smoke\n";
+
+require_once __DIR__ . '/agents-api-smoke-helpers.php';
+agents_api_smoke_require_module();
+
+final class Agents_API_Smoke_Runtime_Profile_Provider implements WP_Agent_Runtime_Profile_Provider {
+	public function resolve_agent_runtime_profile( WP_Agent $agent, array $context ): ?WP_Agent_Runtime_Profile {
+		unset( $context );
+
+		return new WP_Agent_Runtime_Profile(
+			$agent->get_slug(),
+			'host-provider',
+			'host-model',
+			null,
+			array(
+				'provider_id'    => array( 'source' => 'host', 'path' => 'provider_id' ),
+				'model_id'       => array( 'source' => 'host', 'path' => 'model_id' ),
+				'config_sources' => array( array( 'source' => 'host', 'path' => 'profile' ) ),
+			)
+		);
+	}
+}
+
+add_action(
+	'wp_agents_api_init',
+	static function () {
+		wp_register_agent(
+			'runtime-profile-agent',
+			array(
+				'default_config' => array(
+					'mode_models'      => array(
+						'design' => array(
+							'provider_id' => 'mode-provider',
+							'model_id'    => 'mode-model',
+						),
+					),
+					'default_provider' => 'fallback-provider',
+					'default_model'    => 'fallback-model',
+				),
+			)
+		);
+	}
+);
+
+do_action( 'init' );
+
+$agent = wp_get_agent( 'runtime-profile-agent' );
+agents_api_smoke_assert_equals( true, $agent instanceof WP_Agent, 'agent registered for runtime profile smoke', $failures, $passes );
+
+$explicit = wp_resolve_agent_runtime_profile(
+	$agent,
+	array(
+		'provider_id' => 'context-provider',
+		'model'       => array( 'model_id' => 'context-model' ),
+		'mode'        => 'design',
+	)
+);
+agents_api_smoke_assert_equals( 'context-provider', $explicit instanceof WP_Agent_Runtime_Profile ? $explicit->provider_id() : null, 'explicit provider override wins', $failures, $passes );
+agents_api_smoke_assert_equals( 'context-model', $explicit instanceof WP_Agent_Runtime_Profile ? $explicit->model_id() : null, 'explicit nested model override wins', $failures, $passes );
+agents_api_smoke_assert_equals( array( 'source' => 'context', 'path' => 'provider_id' ), $explicit instanceof WP_Agent_Runtime_Profile ? $explicit->provenance()['provider_id'] : null, 'explicit provider provenance records context override', $failures, $passes );
+
+$mode_profile = wp_resolve_agent_runtime_profile( 'runtime-profile-agent', array( 'mode' => 'design' ) );
+agents_api_smoke_assert_equals( 'mode-provider', $mode_profile instanceof WP_Agent_Runtime_Profile ? $mode_profile->provider_id() : null, 'mode provider resolves from default config', $failures, $passes );
+agents_api_smoke_assert_equals( 'mode-model', $mode_profile instanceof WP_Agent_Runtime_Profile ? $mode_profile->model_id() : null, 'mode model resolves from default config', $failures, $passes );
+agents_api_smoke_assert_equals( 'mode_models.design.provider_id', $mode_profile instanceof WP_Agent_Runtime_Profile ? $mode_profile->provenance()['provider_id']['path'] : null, 'mode provider provenance path is stable', $failures, $passes );
+agents_api_smoke_assert_equals( 'mode_models.design.model_id', $mode_profile instanceof WP_Agent_Runtime_Profile ? $mode_profile->provenance()['model_id']['path'] : null, 'mode model provenance path is stable', $failures, $passes );
+
+$default_profile = wp_resolve_agent_runtime_profile( $agent, array( 'mode' => 'unknown' ) );
+agents_api_smoke_assert_equals( 'fallback-provider', $default_profile instanceof WP_Agent_Runtime_Profile ? $default_profile->provider_id() : null, 'default provider resolves without mode match', $failures, $passes );
+agents_api_smoke_assert_equals( 'fallback-model', $default_profile instanceof WP_Agent_Runtime_Profile ? $default_profile->model_id() : null, 'default model resolves without mode match', $failures, $passes );
+
+$host_profile = wp_resolve_agent_runtime_profile(
+	$agent,
+	array(
+		'runtime_profile_providers' => array( new Agents_API_Smoke_Runtime_Profile_Provider() ),
+	)
+);
+agents_api_smoke_assert_equals( 'host-provider', $host_profile instanceof WP_Agent_Runtime_Profile ? $host_profile->provider_id() : null, 'host profile provider is honored before config', $failures, $passes );
+agents_api_smoke_assert_equals( 'host-model', $host_profile instanceof WP_Agent_Runtime_Profile ? $host_profile->model_id() : null, 'host profile model is honored before config', $failures, $passes );
+
+agents_api_smoke_assert_equals(
+	array(
+		'agent_slug'  => 'runtime-profile-agent',
+		'provider_id' => 'host-provider',
+		'model_id'    => 'host-model',
+		'identity'    => null,
+		'provenance'  => $host_profile instanceof WP_Agent_Runtime_Profile ? $host_profile->provenance() : array(),
+	),
+	$host_profile instanceof WP_Agent_Runtime_Profile ? $host_profile->to_array() : null,
+	'runtime profile to_array shape is stable',
+	$failures,
+	$passes
+);
+
+agents_api_smoke_finish( 'Agents API runtime profile', $failures, $passes );