`kebab fetch chunk|doc|span` 신규 subcommand + MCP `kebab__fetch`
tool. wire = `fetch_result.v1` (kind discriminator).

source = CanonicalDocument / chunks.text 정규화된 markdown (raw
bytes 미노출). chunk mode `--context N` = ordinal ±N. doc/span
mode = fb-34 budget 재사용 (chars/4). PDF/audio span 은
`error.v1.code = span_not_supported` 거절.

신규 error codes: chunk_not_found / doc_not_found /
span_not_supported / invalid_input. fb-34 StructuredError
wrapper 재사용.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

@@ -0,0 +196,4 @@
+    )? {
+        if matches!(
+            asset.media_type,
+            kebab_core::MediaType::Pdf | kebab_core::MediaType::Audio(_)

@@ -0,0 +227,4 @@
+    let full = fmt_canonical_to_markdown(&doc);
+    let lines: Vec<&str> = full.lines().collect();
+    let total = lines.len() as u32;
+    let effective_end_raw = line_end.min(total).max(line_start);

@@ -0,0 +232,4 @@
+    let hi = effective_end_raw as usize;
+    let mut text = lines[lo..hi].join("\n");
+
+    let mut truncated = effective_end_raw != line_end;

@@ -0,0 +285,4 @@
+        .ok_or_else(|| anyhow::anyhow!("chunk not found in doc chunk list"))?;
+    let n = n as usize;
+    let lo = target_idx.saturating_sub(n);
+    let hi = (target_idx + n + 1).min(chunks.len());

@@ -0,0 +336,4 @@
+            Block::Paragraph(t) => out.push_str(&t.text),
+            Block::Quote(t) => {
+                // Prefix every line with `> ` so block-quote round-trips.
+                for (li, line) in t.text.split('\n').enumerate() {

@@ -1115,0 +1206,4 @@
+            if let Some(c) = &r.chunk {
+                println!("\n=== target ===");
+                let heading = c.heading_path.last().map(|s| s.as_str()).unwrap_or("");
+                println!("[{} § {}]\n{}\n", c.chunk_id.0, heading, c.text);

@@ -0,0 +53,4 @@
+                "unknown kind '{other}'; expected chunk|doc|span"
+            ));
+        }
+    };

@@ -72,0 +83,4 @@
+
+- `chunk` mode: `context: N` returns ordinal-adjacent chunks before/after for surrounding paragraphs.
+- `doc` mode: full normalized markdown. `max_tokens` (chars/4) caps the response — `truncated: true` when applied.
+- `span` mode: 1-based inclusive line range. PDF / audio docs reject as `error.v1.code = span_not_supported` (use `chunk` mode instead — PDF chunks are page-aligned).

@@ -0,0 +196,4 @@
+    )? {
+        if matches!(
+            asset.media_type,
+            kebab_core::MediaType::Pdf | kebab_core::MediaType::Audio(_)

@@ -0,0 +255,4 @@
+            line_end: Some(line_end),
+            // saturating_sub: when line_start = 1 we end at 0, signaling
+            // "no lines fetched" without underflowing u32.
+            effective_end: Some(line_start.saturating_sub(1)),

@@ -0,0 +269,4 @@
+    // budget-driven truncation only. Line-range clamp (line_end >
+    // total) is signaled via `effective_end < line_end`, not via
+    // `truncated`.
+    let mut truncated = false;

@@ -0,0 +323,4 @@
+    let n = n as usize;
+    let lo = target_idx.saturating_sub(n);
+    let hi = target_idx
+        .saturating_add(n)

@@ -0,0 +315,4 @@
+    assert!(
+        result.context_before.len() + result.context_after.len() <= 4,
+        "doc boundary should clamp ±N to fit chunk count"
+    );

@@ -378,0 +386,4 @@
+    /// all chunks share `created_at` to the millisecond, so the
+    /// secondary `chunk_id` sort dominates and the "neighbors"
+    /// returned here may not be document-adjacent.
+    ///

@@ -0,0 +18,4 @@
+    "text":           { "type": "string", "description": "kind=doc/span: markdown text (truncated if budget tripped)" },
+    "line_start":     { "type": ["integer", "null"], "minimum": 1, "description": "kind=span: requested start line (1-based)" },
+    "line_end":       { "type": ["integer", "null"], "minimum": 1, "description": "kind=span: requested end line (1-based, inclusive)" },
+    "effective_end":  { "type": ["integer", "null"], "minimum": 1, "description": "kind=span: actual emitted end line after budget truncation" },

@@ -0,0 +323,4 @@
+    // follow-up: V007 chunks.ordinal migration.
+    let total = result.context_before.len() + result.context_after.len();
+    assert!(
+        total <= 2,

@@ -378,0 +393,4 @@
+    /// they may or may not align with document position depending on
+    /// whether `chunk_id` hash order happens to match insertion order
+    /// for that particular doc. Large markdown / PDF (page-aligned
+    /// chunks) likely re-orders. See `tasks/HOTFIXES.md` if escalated.

@@ -0,0 +18,4 @@
+    "text":           { "type": "string", "description": "kind=doc/span: markdown text (truncated if budget tripped)" },
+    "line_start":     { "type": ["integer", "null"], "minimum": 1, "description": "kind=span: requested start line (1-based)" },
+    "line_end":       { "type": ["integer", "null"], "minimum": 1, "description": "kind=span: requested end line (1-based, inclusive)" },
+    "effective_end":  { "type": ["integer", "null"], "minimum": 0, "description": "kind=span: actual end line of emitted text (1-based, inclusive). Equals `line_end` on full slice; less than `line_end` when (a) requested range exceeded total lines (line clamp) or (b) `--max-tokens` budget trimmed the tail. Special case: `line_start - 1` (which is 0 when line_start=1) signals the entire requested range was beyond doc end — returned `text` is empty." },