zeta2: Add labeled sections prompt format (#38828)

Release Notes:

- N/A

Co-authored-by: Agus <agus@zed.dev>

crates/zeta_cli/src/main.rs

@@ -2,6 +2,7 @@ mod headless;
 
 use anyhow::{Result, anyhow};
 use clap::{Args, Parser, Subcommand};
+use cloud_llm_client::predict_edits_v3::PromptFormat;
 use edit_prediction_context::EditPredictionExcerptOptions;
 use futures::channel::mpsc;
 use futures::{FutureExt as _, StreamExt as _};
@@ -74,6 +75,16 @@ struct Zeta2Args {
     target_before_cursor_over_total_bytes: f32,
     #[arg(long, default_value_t = 1024)]
     max_diagnostic_bytes: usize,
+    #[arg(long, value_parser = parse_format)]
+    format: PromptFormat,
+}
+
+fn parse_format(s: &str) -> Result<PromptFormat> {
+    match s {
+        "marked_excerpt" => Ok(PromptFormat::MarkedExcerpt),
+        "labeled_sections" => Ok(PromptFormat::LabeledSections),
+        _ => Err(anyhow!("Invalid format: {}", s)),
+    }
 }
 
 #[derive(Debug, Clone)]
@@ -228,6 +239,7 @@ async fn get_context(
                         },
                         max_diagnostic_bytes: zeta2_args.max_diagnostic_bytes,
                         max_prompt_bytes: zeta2_args.max_prompt_bytes,
+                        prompt_format: zeta2_args.format,
                     })
                 });
                 // TODO: Actually wait for indexing.
@@ -240,13 +252,9 @@ async fn get_context(
                             zeta.cloud_request_for_zeta_cli(&project, &buffer, cursor, cx)
                         })?
                         .await?;
-                    let planned_prompt = cloud_zeta2_prompt::PlannedPrompt::populate(
-                        &request,
-                        &cloud_zeta2_prompt::PlanOptions {
-                            max_bytes: zeta2_args.max_prompt_bytes,
-                        },
-                    )?;
-                    anyhow::Ok(planned_prompt.to_prompt_string())
+                    let planned_prompt = cloud_zeta2_prompt::PlannedPrompt::populate(&request)?;
+                    // TODO: Output the section label ranges
+                    anyhow::Ok(planned_prompt.to_prompt_string()?.0)
                 })
             })?
             .await?,