diff --git a/crates/busbar-plane-llm/src/codec/anthropic/tests/ir_mapping_q57_tests.rs b/crates/busbar-plane-llm/src/codec/anthropic/tests/ir_mapping_q57_tests.rs
index 3dda799761..2f18a364d7 100644
--- a/crates/busbar-plane-llm/src/codec/anthropic/tests/ir_mapping_q57_tests.rs
+++ b/crates/busbar-plane-llm/src/codec/anthropic/tests/ir_mapping_q57_tests.rs
@@ -734,3 +734,46 @@ fn ant18_search_result_citation_source_maps_both_ways() {
                "title": "KB", "search_result_index": 0, "start_block_index": 0, "end_block_index": 1}),
     );
 }
+
+/// F25 REHOME row 110, from `crates/busbar-llm/src/engine/tests/egress_dropped_controls_audit_tests.rs:245`
+/// (`native_structured_output_lane_drops_schema_less_json_with_audit`): on a lane declaring native
+/// structured outputs a `json_schema` directive rides `output_config.format.type: json_schema` with no
+/// `tool_choice`; a schema-less `json_object` writes no `output_config` and no `tools`, and is reported
+/// as the dropped control `response_format` (the caller's `response_format on anthropic` audit row).
+#[test]
+fn native_structured_output_lane_drops_schema_less_json_and_reports_it() {
+    let native = busbar_contract::ir::egress_prep::LaneCaps {
+        native_structured_output: true,
+        ..Default::default()
+    };
+    let schema = json!({"type": "object", "properties": {"a": {"type": "string"}}});
+    let with_schema = xreq_lane(
+        "openai",
+        "anthropic",
+        &json!({"model": "gpt-4o", "messages": [{"role": "user", "content": "hi"}],
+               "response_format": {"type": "json_schema", "json_schema": {"name": "o", "schema": schema}}}),
+        &native,
+    );
+    assert_eq!(
+        with_schema.pointer("/output_config/format/type"),
+        Some(&json!("json_schema")),
+        "{with_schema}"
+    );
+    assert!(with_schema.get("tool_choice").is_none(), "{with_schema}");
+
+    let object_body = json!({"model": "gpt-4o", "messages": [{"role": "user", "content": "hi"}],
+                             "response_format": {"type": "json_object"}});
+    let object_mode = xreq_lane("openai", "anthropic", &object_body, &native);
+    assert!(object_mode.get("output_config").is_none(), "{object_mode}");
+    assert!(object_mode.get("tools").is_none(), "{object_mode}");
+    let ir = protocol_for("openai")
+        .unwrap()
+        .reader()
+        .read_request(&object_body)
+        .unwrap();
+    assert!(protocol_for("anthropic")
+        .unwrap()
+        .writer()
+        .dropped_egress_controls_for_lane(&ir, &native)
+        .contains(&"response_format"));
+}
diff --git a/crates/busbar-plane-llm/src/codec/bedrock/tests/tests.rs b/crates/busbar-plane-llm/src/codec/bedrock/tests/tests.rs
index d108b63a45..33dbd53cff 100644
--- a/crates/busbar-plane-llm/src/codec/bedrock/tests/tests.rs
+++ b/crates/busbar-plane-llm/src/codec/bedrock/tests/tests.rs
@@ -6771,3 +6771,67 @@ fn the_tails_sigv4_parameters_restate_the_signing_scheme() {
         .as_str()
         .is_some_and(|w| w.contains("defaulting SigV4 scope to us-east-1")));
 }
+
+// ── F25 REHOME (row 108) ─────────────────────────────────────────────────────────────────────────
+
+/// The production request translate steps (reader → egress seam → writer → shim strip), with the
+/// prepared IR beside the written body.
+fn rehome_xreq(
+    ingress: &'static str,
+    egress: &str,
+    body: &serde_json::Value,
+) -> (crate::codec::ir::IrRequest, serde_json::Value) {
+    let ingress_p = crate::codec::proto_codec::protocol_for(ingress).expect("ingress");
+    let egress_p = crate::codec::proto_codec::protocol_for(egress).expect("egress");
+    let mut req = ingress_p.reader().read_request(body).expect("read_request");
+    crate::codec::chat_handle::chat_prepare_for_egress(
+        &mut req,
+        &busbar_contract::ir::egress_prep::EgressPrep {
+            thought_signature_fill: false,
+            ingress_protocol: ingress,
+            egress_requires_max_tokens: egress_p.decl().is_some_and(|d| d.requires_max_tokens),
+            lane_default_max_tokens: None,
+            global_default_max_tokens: 4096,
+            reasoning_allowed: true,
+            reasoning_budgets: crate::codec::ir::REASONING_BUDGET_DEFAULTS,
+            prompt_caching_allowed: true,
+            cache_control_cap: None,
+            lane_caps: Default::default(),
+        },
+    );
+    let mut out = egress_p.writer().write_request(&req);
+    crate::codec::wire_shim::strip_router_shim_keys(&mut out, egress);
+    (req, out)
+}
+
+/// F25 REHOME row 108, from `crates/busbar-llm/src/engine/tests/egress_dropped_controls_audit_tests.rs:89`
+/// (`openai_to_bedrock_tool_choice_none_forwards_and_audits_degraded`): an OpenAI caller's tools plus
+/// `tool_choice: "none"` onto Bedrock still forwards (a non-empty body, the tool kept, `toolChoice`
+/// omitted: Converse has no "do not call a tool"), and the drop is reported as the control
+/// `tool_choice=none`, the name the caller's `egress.control_unrepresentable` audit row carries
+/// (`tool_choice=none on bedrock`).
+#[test]
+fn openai_tool_choice_none_onto_bedrock_forwards_and_reports_the_drop() {
+    let body = serde_json::json!({
+        "model": "gpt-4o",
+        "messages": [{"role": "user", "content": "hi"}],
+        "tools": [{
+            "type": "function",
+            "function": {"name": "get_weather", "parameters": {"type": "object"}}
+        }],
+        "tool_choice": "none"
+    });
+    let (req, out) = rehome_xreq("openai", "bedrock", &body);
+    assert!(out.as_object().is_some_and(|o| !o.is_empty()), "{out}");
+    assert_eq!(
+        out.pointer("/toolConfig/tools/0/toolSpec/name"),
+        Some(&serde_json::json!("get_weather")),
+        "{out}"
+    );
+    assert!(out.pointer("/toolConfig/toolChoice").is_none(), "{out}");
+    let dropped = crate::codec::proto_codec::protocol_for("bedrock")
+        .expect("bedrock")
+        .writer()
+        .dropped_egress_controls(&req);
+    assert!(dropped.contains(&"tool_choice=none"), "{dropped:?}");
+}
diff --git a/crates/busbar-plane-llm/src/codec/tests/proto/response_format_matrix_tests.rs b/crates/busbar-plane-llm/src/codec/tests/proto/response_format_matrix_tests.rs
index 4006c7d9fe..b1c82ec355 100644
--- a/crates/busbar-plane-llm/src/codec/tests/proto/response_format_matrix_tests.rs
+++ b/crates/busbar-plane-llm/src/codec/tests/proto/response_format_matrix_tests.rs
@@ -391,3 +391,71 @@ fn parallel_tool_calls_discarded_on_gemini_cohere_bedrock_warns() {
         cap2.messages()
     );
 }
+
+// ── F25 REHOME (rows 613, 614): the Cohere stop-sequence cap ─────────────────────────────────────
+
+/// The production request translate steps onto `egress` (reader → egress seam → writer).
+fn rehome_xreq(ingress: &'static str, egress: &str, body: &serde_json::Value) -> serde_json::Value {
+    let ingress_p = crate::codec::proto_codec::protocol_for(ingress).expect("ingress");
+    let egress_p = crate::codec::proto_codec::protocol_for(egress).expect("egress");
+    let mut req = ingress_p.reader().read_request(body).expect("read_request");
+    crate::codec::chat_handle::chat_prepare_for_egress(
+        &mut req,
+        &busbar_contract::ir::egress_prep::EgressPrep {
+            thought_signature_fill: false,
+            ingress_protocol: ingress,
+            egress_requires_max_tokens: egress_p.decl().is_some_and(|d| d.requires_max_tokens),
+            lane_default_max_tokens: None,
+            global_default_max_tokens: 4096,
+            reasoning_allowed: true,
+            reasoning_budgets: crate::codec::ir::REASONING_BUDGET_DEFAULTS,
+            prompt_caching_allowed: true,
+            cache_control_cap: None,
+            lane_caps: Default::default(),
+        },
+    );
+    egress_p.writer().write_request(&req)
+}
+
+/// F25 REHOME row 613, from `crates/busbar-llm/src/engine/tests/stop_sequence_cap_degrade_tests.rs:23`
+/// (`openai_to_cohere_over_cap_stop_sequences_is_clamped_not_rejected`): an OpenAI caller's six stop
+/// sequences onto a Cohere lane are CLAMPED to Cohere's cap of 5 and forwarded, not rejected
+/// (v1.5.4's truncate-and-forward).
+#[test]
+fn openai_to_cohere_over_cap_stop_sequences_are_clamped_not_rejected() {
+    let out = rehome_xreq(
+        "openai",
+        "cohere",
+        &serde_json::json!({
+            "model": "gpt-4o",
+            "messages": [{"role": "user", "content": "hi"}],
+            "stop": ["a", "b", "c", "d", "e", "f"]
+        }),
+    );
+    assert_eq!(
+        out.get("stop_sequences"),
+        Some(&serde_json::json!(["a", "b", "c", "d", "e"])),
+        "an over-cap stop list is clamped to Cohere's cap of 5: {out}"
+    );
+}
+
+/// F25 REHOME row 614, from `crates/busbar-llm/src/engine/tests/stop_sequence_cap_degrade_tests.rs:63`
+/// (`openai_to_cohere_exactly_cap_stop_sequences_is_allowed`): exactly five stop sequences is within
+/// Cohere's cap and is forwarded whole.
+#[test]
+fn openai_to_cohere_exactly_cap_stop_sequences_are_forwarded_whole() {
+    let out = rehome_xreq(
+        "openai",
+        "cohere",
+        &serde_json::json!({
+            "model": "gpt-4o",
+            "messages": [{"role": "user", "content": "hi"}],
+            "stop": ["a", "b", "c", "d", "e"]
+        }),
+    );
+    assert_eq!(
+        out.get("stop_sequences"),
+        Some(&serde_json::json!(["a", "b", "c", "d", "e"])),
+        "an at-cap stop list is forwarded whole: {out}"
+    );
+}
diff --git a/crates/busbar-plane-llm/src/codec/tests/proto/stream_translate_tests.rs b/crates/busbar-plane-llm/src/codec/tests/proto/stream_translate_tests.rs
index 54bd198ef1..b51434b9f7 100644
--- a/crates/busbar-plane-llm/src/codec/tests/proto/stream_translate_tests.rs
+++ b/crates/busbar-plane-llm/src/codec/tests/proto/stream_translate_tests.rs
@@ -5081,3 +5081,53 @@ fn responses_failed_stream_bills_its_reported_usage() {
     assert!(none.usage().is_none());
     assert!(none.terminal_error().is_some());
 }
+
+/// F25 REHOME row 350, from `crates/busbar-llm/src/engine/tests/ingress_indistinguishability_tests.rs:2234`
+/// (`test_forward_once_cross_protocol_remaps_tool_call_id`): an Anthropic answer whose `tool_use` id
+/// is `toolu_origRAW123`, delivered to an OpenAI caller through the production ingress seam
+/// (`chat_prepare_for_ingress`, which every attempt path runs), carries an OpenAI-native `call_…`
+/// id, never the raw one, and the raw id appears nowhere in the client body. The client's echo of
+/// that id decodes back to the far end's original.
+#[test]
+fn an_anthropic_tool_call_id_reaches_an_openai_client_remapped_and_unleaked() {
+    let ir_resp = AnthropicReader
+        .read_response(&serde_json::json!({
+            "id": "msg_x",
+            "type": "message",
+            "role": "assistant",
+            "content": [{
+                "type": "tool_use",
+                "id": "toolu_origRAW123",
+                "name": "get_weather",
+                "input": {"city": "SF"}
+            }],
+            "model": "claude-3",
+            "stop_reason": "tool_use",
+            "usage": {"input_tokens": 3, "output_tokens": 2}
+        }))
+        .expect("anthropic read");
+    let mut ir_resp = ir_resp;
+    crate::codec::chat_handle::chat_prepare_for_ingress(&mut ir_resp, "openai", 1_752_000_000);
+    let body = crate::codec::proto_codec::protocol_for("openai")
+        .expect("openai")
+        .writer()
+        .write_response(&ir_resp);
+    let tool_id = body
+        .pointer("/choices/0/message/tool_calls/0/id")
+        .and_then(|s| s.as_str())
+        .unwrap_or_else(|| panic!("expected an OpenAI tool_calls id in: {body}"))
+        .to_string();
+    assert!(tool_id.starts_with("call_"), "{tool_id}");
+    assert_ne!(tool_id, "toolu_origRAW123");
+    let bytes = serde_json::to_vec(&body).expect("serializes");
+    assert!(
+        !bytes
+            .windows("toolu_origRAW123".len())
+            .any(|w| w == b"toolu_origRAW123"),
+        "the raw Anthropic tool id must not appear anywhere in the client body: {body}"
+    );
+    assert_eq!(
+        decode_native_tool_id("openai", &tool_id).as_deref(),
+        Some("toolu_origRAW123")
+    );
+}
diff --git a/crates/busbar-plane-llm/src/codec/tests/wire_shim_tests.rs b/crates/busbar-plane-llm/src/codec/tests/wire_shim_tests.rs
index c4557c2832..f68c4f28b4 100644
--- a/crates/busbar-plane-llm/src/codec/tests/wire_shim_tests.rs
+++ b/crates/busbar-plane-llm/src/codec/tests/wire_shim_tests.rs
@@ -297,3 +297,92 @@ fn a_transcription_duration_ledgers_one_audio_ms_line() {
 fn a_flat_answer_ledgers_no_open_class() {
     assert!(non_token_open(busbar_contract::billing::Billing::Flat).is_empty());
 }
+
+// ── F25 REHOME (rows 504, 505): the router shim keys ─────────────────────────────────────────────
+
+const SHIM: &str = crate::codec::gemini::GEMINI_JSON_ARRAY_SHIM_KEY;
+
+/// F25 REHOME row 504, from `crates/busbar-llm/src/engine/tests/mid_stream_error_tests.rs:294` (`test_strip_router_shim_keys`):
+/// `strip_router_shim_keys` removes the never-native shim keys per egress — the gemini array key for
+/// every egress, `stream` for a path-model egress (bedrock, gemini) — and never `model`; a
+/// body-model egress (openai) keeps its genuine `model` and `stream`.
+#[test]
+fn strip_router_shim_keys_removes_the_never_native_keys_per_egress() {
+    use super::strip_router_shim_keys;
+    use serde_json::json;
+    let mut v = json!({"model": "p", "stream": true, (SHIM): true, "messages": []});
+    assert!(strip_router_shim_keys(&mut v, "bedrock"));
+    assert_eq!(
+        v["model"], "p",
+        "model NOT stripped here (rewrite_model owns it)"
+    );
+    assert!(v.get("stream").is_none(), "bedrock: stream shim stripped");
+    assert!(
+        v.get(SHIM).is_none(),
+        "gemini array shim key stripped on every protocol"
+    );
+    assert!(v.get("messages").is_some(), "real fields retained");
+
+    let mut v = json!({"stream": true, (SHIM): true});
+    assert!(strip_router_shim_keys(&mut v, "gemini"));
+    assert!(v.get("stream").is_none() && v.get(SHIM).is_none());
+
+    let mut v = json!({"model": "gpt-4o", "stream": true, (SHIM): true});
+    assert!(strip_router_shim_keys(&mut v, "openai"));
+    assert_eq!(
+        v["model"], "gpt-4o",
+        "openai model is genuine, not stripped"
+    );
+    assert_eq!(v["stream"], true, "openai stream is genuine, not stripped");
+    assert!(
+        v.get(SHIM).is_none(),
+        "gemini array key stripped even for body-model ingress"
+    );
+}
+
+/// F25 REHOME row 505, from `crates/busbar-llm/src/engine/tests/mid_stream_error_tests.rs:337`
+/// (`test_shim_strip_ordering_cross_protocol_keeps_model`): a path-model ingress (gemini) crossing to
+/// a body-model egress (openai) reaches the far end WITH the authoritative model: strip, then
+/// `rewrite_model_if_needed`, leaves `model: gpt-4o` and the writer-authored `stream: true`, with
+/// the array key gone; within one dialect (gemini→gemini) the relay sends the caller's own bytes,
+/// with the spliced `model` and `stream` removed.
+#[test]
+fn shim_strip_then_rewrite_model_keeps_the_model_cross_protocol() {
+    use super::strip_router_shim_keys;
+    use serde_json::json;
+    let mut v = json!({"model": "router-placeholder", "stream": true, (SHIM): true});
+    strip_router_shim_keys(&mut v, "openai");
+    crate::codec::proto_codec::protocol_for("openai")
+        .expect("openai")
+        .writer()
+        .rewrite_model_if_needed(&mut v, "gpt-4o");
+    assert_eq!(
+        v["model"], "gpt-4o",
+        "cross-protocol egress body MUST carry the authoritative model"
+    );
+    assert_eq!(
+        v["stream"], true,
+        "writer-authored `stream` survives for a body-model egress"
+    );
+    assert!(
+        v.get(SHIM).is_none(),
+        "gemini array key stripped cross-protocol"
+    );
+
+    let caller = br#"{ "contents": [ ], "z" : 1.0 }"#;
+    let carried = br#"{"model":"router-placeholder","stream":true, "contents": [ ], "z" : 1.0 }"#;
+    let far = crate::exchange::shaping::FarShape {
+        dialect: "gemini",
+        wire_model: "gemini-1.5-pro",
+        default_max_tokens: None,
+        prompt_caching: false,
+        caps: Default::default(),
+        path_base: None,
+    };
+    let relayed = crate::exchange::attempt::relay_request(far, "application/json", carried);
+    assert_eq!(
+        relayed.bytes.as_ref(),
+        caller.as_slice(),
+        "same-protocol gemini relay sends the caller's bytes, no body model or stream"
+    );
+}