fix(tui): bill Anthropic cache-write tokens at published rates

Keep cache-creation usage separate from cache-miss and wire
CurrencyPricing.cache_write so TUI cost estimates stop undercounting
Anthropic/Qwen write premiums (#4318).

Author: knqiufan

crates/tui/src/client.rs

@@ -2238,6 +2238,7 @@ pub(super) fn parse_usage(usage: Option<&Value>) -> Usage {
         output_tokens: output_tokens.min(u64::from(u32::MAX)) as u32,
         prompt_cache_hit_tokens,
         prompt_cache_miss_tokens,
+        prompt_cache_write_tokens: None,
         reasoning_tokens,
         reasoning_replay_tokens: None,
         server_tool_use,

crates/tui/src/client/anthropic.rs

@@ -11,10 +11,11 @@
 //!   CodeWhale's `reasoning_effort` tiers, sampling-parameter rules for
 //!   models that reject them, and `cache_control` breakpoint placement
 //!   aligned with the prefix-zone model in `prefix_cache.rs`;
-//! - usage normalization (#2961): `prompt_cache_hit_tokens` comes from
-//!   `cache_read_input_tokens`, `prompt_cache_miss_tokens` is `input_tokens`
-//!   plus `cache_creation_input_tokens`, and the normalized `input_tokens`
-//!   is the sum of all three (total prompt, the DeepSeek convention);
+//! - usage normalization (#2961 / #4318): `prompt_cache_hit_tokens` comes from
+//!   `cache_read_input_tokens`, `prompt_cache_write_tokens` from
+//!   `cache_creation_input_tokens`, `prompt_cache_miss_tokens` is the raw
+//!   non-cached `input_tokens`, and the normalized `input_tokens` is the sum
+//!   of all three (total prompt, the DeepSeek convention);
 //! - signed-thinking handling: `signature_delta` is captured into
 //!   [`crate::models::Delta::SignatureDelta`] and assistant thinking blocks
 //!   replay verbatim (signature included); unsigned thinking blocks are
@@ -496,8 +497,8 @@ fn convert_anthropic_sse_data(data: &str) -> Option<Result<StreamEvent>> {
 }
 
 /// Map Anthropic's usage payload onto the normalized [`Usage`] convention
-/// (#2961): hit = cache reads, miss = uncached input + cache writes,
-/// `input_tokens` = the total prompt across all three.
+/// (#2961 / #4318): hit = cache reads, write = cache creation, miss = raw
+/// uncached input, `input_tokens` = the total prompt across all three.
 fn parse_anthropic_usage(usage: &Value) -> Usage {
     let field = |name: &str| {
         usage
@@ -517,7 +518,8 @@ fn parse_anthropic_usage(usage: &Value) -> Usage {
             .saturating_add(cache_read),
         output_tokens: output,
         prompt_cache_hit_tokens: Some(cache_read),
-        prompt_cache_miss_tokens: Some(input_raw.saturating_add(cache_creation)),
+        prompt_cache_miss_tokens: Some(input_raw),
+        prompt_cache_write_tokens: Some(cache_creation),
         reasoning_tokens: None,
         reasoning_replay_tokens: None,
         server_tool_use: None,
@@ -852,7 +854,8 @@ mod tests {
         };
         assert_eq!(message.usage.input_tokens, 3 + 2045 + 18000);
         assert_eq!(message.usage.prompt_cache_hit_tokens, Some(18000));
-        assert_eq!(message.usage.prompt_cache_miss_tokens, Some(3 + 2045));
+        assert_eq!(message.usage.prompt_cache_miss_tokens, Some(3));
+        assert_eq!(message.usage.prompt_cache_write_tokens, Some(2045));
 
         assert!(matches!(
             &decoded[1],
@@ -927,6 +930,21 @@ mod tests {
         assert_eq!(usage.output_tokens, 5);
         assert_eq!(usage.prompt_cache_hit_tokens, Some(0));
         assert_eq!(usage.prompt_cache_miss_tokens, Some(10));
+        assert_eq!(usage.prompt_cache_write_tokens, Some(0));
+    }
+
+    #[test]
+    fn usage_mapping_keeps_cache_write_separate_from_miss() {
+        let usage = parse_anthropic_usage(&json!({
+            "input_tokens": 3,
+            "cache_creation_input_tokens": 2045,
+            "cache_read_input_tokens": 18000,
+            "output_tokens": 1,
+        }));
+        assert_eq!(usage.input_tokens, 3 + 2045 + 18000);
+        assert_eq!(usage.prompt_cache_hit_tokens, Some(18000));
+        assert_eq!(usage.prompt_cache_miss_tokens, Some(3));
+        assert_eq!(usage.prompt_cache_write_tokens, Some(2045));
     }
 
     #[test]

crates/tui/src/client/responses.rs

@@ -707,6 +707,7 @@ fn parse_responses_usage(val: &Value) -> Usage {
         output_tokens: output,
         prompt_cache_hit_tokens,
         prompt_cache_miss_tokens,
+        prompt_cache_write_tokens: None,
         reasoning_tokens,
         reasoning_replay_tokens: None,
         server_tool_use: None,

crates/tui/src/core/engine.rs

@@ -2069,8 +2069,8 @@ impl Engine {
         if let Some(hit_tokens) = usage.cache_read_input_tokens {
             line.push_str(&format!(", cache hits {hit_tokens}"));
         }
-        if let Some(miss_tokens) = usage.cache_creation_input_tokens {
-            line.push_str(&format!(", cache misses {miss_tokens}"));
+        if let Some(write_tokens) = usage.cache_creation_input_tokens {
+            line.push_str(&format!(", cache writes {write_tokens}"));
         }
         Some(line)
     }

crates/tui/src/core/engine/tests.rs

@@ -5461,6 +5461,7 @@ fn turn_metadata_surfaces_context_and_resource_usage() {
         output_tokens: 300,
         prompt_cache_hit_tokens: Some(800),
         prompt_cache_miss_tokens: Some(400),
+        prompt_cache_write_tokens: Some(400),
         ..Default::default()
     });
     {
@@ -5487,7 +5488,7 @@ fn turn_metadata_surfaces_context_and_resource_usage() {
         "session usage should be model-visible: {text}"
     );
     assert!(text.contains("cache hits 800"), "got: {text}");
-    assert!(text.contains("cache misses 400"), "got: {text}");
+    assert!(text.contains("cache writes 400"), "got: {text}");
     assert!(
         text.contains("Active goal resource usage:"),
         "active goal resource usage should be model-visible: {text}"

crates/tui/src/core/session.rs

@@ -98,8 +98,8 @@ pub struct Session {
 pub struct SessionUsage {
     pub input_tokens: u64,
     pub output_tokens: u64,
-    /// Cache creation (miss) tokens. `None` when never observed by the API —
-    /// do NOT display as 0, which would be indistinguishable from "no misses".
+    /// Cache creation (write) tokens. `None` when never observed by the API —
+    /// do NOT display as 0, which would be indistinguishable from "no writes".
     pub cache_creation_input_tokens: Option<u64>,
     /// Cache read (hit) tokens. `None` when never observed by the API —
     /// do NOT display as 0, which would be indistinguishable from "no hits".
@@ -111,7 +111,7 @@ impl SessionUsage {
     pub fn add(&mut self, usage: &Usage) {
         self.input_tokens += u64::from(usage.input_tokens);
         self.output_tokens += u64::from(usage.output_tokens);
-        if let Some(tokens) = usage.prompt_cache_miss_tokens {
+        if let Some(tokens) = usage.prompt_cache_write_tokens {
             self.cache_creation_input_tokens =
                 Some(self.cache_creation_input_tokens.unwrap_or(0) + u64::from(tokens));
         }
@@ -218,6 +218,7 @@ mod tests {
             output_tokens: 50,
             prompt_cache_hit_tokens: None,
             prompt_cache_miss_tokens: None,
+            prompt_cache_write_tokens: None,
             reasoning_tokens: None,
             reasoning_replay_tokens: None,
             server_tool_use: None,
@@ -234,17 +235,18 @@ mod tests {
             input_tokens: 100,
             output_tokens: 50,
             prompt_cache_hit_tokens: Some(30),
-            prompt_cache_miss_tokens: Some(70),
+            prompt_cache_miss_tokens: Some(50),
+            prompt_cache_write_tokens: Some(20),
             reasoning_tokens: None,
             reasoning_replay_tokens: None,
             server_tool_use: None,
         };
         usage.add(&api_usage);
         assert_eq!(usage.cache_read_input_tokens, Some(30));
-        assert_eq!(usage.cache_creation_input_tokens, Some(70));
+        assert_eq!(usage.cache_creation_input_tokens, Some(20));
         usage.add(&api_usage);
         assert_eq!(usage.cache_read_input_tokens, Some(60));
-        assert_eq!(usage.cache_creation_input_tokens, Some(140));
+        assert_eq!(usage.cache_creation_input_tokens, Some(40));
     }
 
     #[test]
@@ -254,7 +256,8 @@ mod tests {
             input_tokens: 100,
             output_tokens: 50,
             prompt_cache_hit_tokens: Some(0), // explicit zero from provider
-            prompt_cache_miss_tokens: Some(1234),
+            prompt_cache_miss_tokens: Some(50),
+            prompt_cache_write_tokens: Some(1234),
             reasoning_tokens: None,
             reasoning_replay_tokens: None,
             server_tool_use: None,

crates/tui/src/core/turn.rs

@@ -108,6 +108,10 @@ impl TurnContext {
             self.usage.prompt_cache_miss_tokens,
             usage.prompt_cache_miss_tokens,
         );
+        self.usage.prompt_cache_write_tokens = add_optional_usage(
+            self.usage.prompt_cache_write_tokens,
+            usage.prompt_cache_write_tokens,
+        );
         self.usage.reasoning_tokens =
             add_optional_usage(self.usage.reasoning_tokens, usage.reasoning_tokens);
     }

crates/tui/src/hooks.rs

@@ -1301,6 +1301,7 @@ pub fn turn_end_payload(input: TurnEndPayloadInput<'_>) -> serde_json::Value {
             "output_tokens": input.usage.output_tokens,
             "prompt_cache_hit_tokens": input.usage.prompt_cache_hit_tokens,
             "prompt_cache_miss_tokens": input.usage.prompt_cache_miss_tokens,
+            "prompt_cache_write_tokens": input.usage.prompt_cache_write_tokens,
             "reasoning_tokens": input.usage.reasoning_tokens,
             "reasoning_replay_tokens": input.usage.reasoning_replay_tokens,
         },
@@ -1567,6 +1568,7 @@ NOEQUAL line dropped
             output_tokens: 9,
             prompt_cache_hit_tokens: Some(10),
             prompt_cache_miss_tokens: Some(30),
+            prompt_cache_write_tokens: None,
             reasoning_tokens: Some(4),
             reasoning_replay_tokens: Some(2),
             server_tool_use: None,
@@ -1873,6 +1875,7 @@ printf '%s\n' '{{"text":"stdout is not a mutation contract"}}'
             output_tokens: 3,
             prompt_cache_hit_tokens: None,
             prompt_cache_miss_tokens: None,
+            prompt_cache_write_tokens: None,
             reasoning_tokens: None,
             reasoning_replay_tokens: None,
             server_tool_use: None,

crates/tui/src/llm_response_cache.rs

@@ -94,6 +94,7 @@ mod tests {
                 output_tokens: 7,
                 prompt_cache_hit_tokens: Some(3),
                 prompt_cache_miss_tokens: Some(39),
+                prompt_cache_write_tokens: None,
                 reasoning_tokens: Some(5),
                 reasoning_replay_tokens: Some(2),
                 server_tool_use: None,

crates/tui/src/models.rs

@@ -213,6 +213,10 @@ pub struct Usage {
     pub prompt_cache_hit_tokens: Option<u32>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub prompt_cache_miss_tokens: Option<u32>,
+    /// Cache-creation / cache-write tokens (Anthropic `cache_creation_input_tokens`).
+    /// Billed at the cache-write rate when the pricing row publishes one (#4318).
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub prompt_cache_write_tokens: Option<u32>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub reasoning_tokens: Option<u32>,
     /// Approximate input tokens spent re-sending prior `reasoning_content`