diff --git a/packages/opencode/src/altimate/tools/finops-formatting.ts b/packages/opencode/src/altimate/tools/finops-formatting.ts
index 7996fd1937..c88aa5579a 100644
--- a/packages/opencode/src/altimate/tools/finops-formatting.ts
+++ b/packages/opencode/src/altimate/tools/finops-formatting.ts
@@ -1,7 +1,9 @@
 export function formatBytes(bytes: number): string {
   if (bytes === 0) return "0 B"
+  if (!Number.isFinite(bytes)) return "0 B"
+  const abs = Math.abs(bytes)
   const units = ["B", "KB", "MB", "GB", "TB", "PB"]
-  const i = Math.floor(Math.log(bytes) / Math.log(1024))
+  const i = Math.max(0, Math.min(Math.floor(Math.log(abs) / Math.log(1024)), units.length - 1))
   const value = bytes / Math.pow(1024, i)
   return `${value.toFixed(i === 0 ? 0 : 2)} ${units[i]}`
 }
@@ -9,6 +11,9 @@ export function formatBytes(bytes: number): string {
 export function truncateQuery(text: string, maxLen: number): string {
   if (!text) return "(empty)"
   const oneLine = text.replace(/\s+/g, " ").trim()
+  if (!oneLine) return "(empty)"
+  if (maxLen <= 0) return ""
+  if (maxLen < 4) return oneLine.slice(0, maxLen)
   if (oneLine.length <= maxLen) return oneLine
   return oneLine.slice(0, maxLen - 3) + "..."
 }
diff --git a/packages/opencode/test/altimate/tools/finops-formatting.test.ts b/packages/opencode/test/altimate/tools/finops-formatting.test.ts
new file mode 100644
index 0000000000..6598177d2c
--- /dev/null
+++ b/packages/opencode/test/altimate/tools/finops-formatting.test.ts
@@ -0,0 +1,78 @@
+import { describe, test, expect } from "bun:test"
+import { formatBytes, truncateQuery } from "../../../src/altimate/tools/finops-formatting"
+
+describe("formatBytes: normal cases", () => {
+  test("zero returns 0 B", () => {
+    expect(formatBytes(0)).toBe("0 B")
+  })
+
+  test("exact unit boundaries", () => {
+    expect(formatBytes(1)).toBe("1 B")
+    expect(formatBytes(1024)).toBe("1.00 KB")
+    expect(formatBytes(1024 * 1024)).toBe("1.00 MB")
+    expect(formatBytes(1024 * 1024 * 1024)).toBe("1.00 GB")
+  })
+
+  test("non-boundary values", () => {
+    expect(formatBytes(500)).toBe("500 B")
+    expect(formatBytes(1536)).toBe("1.50 KB")
+  })
+})
+
+describe("formatBytes: edge cases", () => {
+  test("negative bytes displays with sign", () => {
+    expect(formatBytes(-100)).toBe("-100 B")
+    expect(formatBytes(-1536)).toBe("-1.50 KB")
+  })
+
+  test("fractional bytes clamps to B unit", () => {
+    expect(formatBytes(0.5)).toBe("1 B")
+  })
+
+  test("NaN input returns 0 B", () => {
+    expect(formatBytes(NaN)).toBe("0 B")
+  })
+
+  test("Infinity input returns 0 B", () => {
+    expect(formatBytes(Infinity)).toBe("0 B")
+    expect(formatBytes(-Infinity)).toBe("0 B")
+  })
+})
+
+describe("truncateQuery: normal cases", () => {
+  test("empty/falsy input returns (empty)", () => {
+    expect(truncateQuery("", 10)).toBe("(empty)")
+  })
+
+  test("short text returned as-is", () => {
+    expect(truncateQuery("SELECT 1", 50)).toBe("SELECT 1")
+  })
+
+  test("long text truncated with ellipsis", () => {
+    const long = "SELECT * FROM very_long_table_name WHERE id = 1"
+    const result = truncateQuery(long, 20)
+    expect(result.length).toBeLessThanOrEqual(20)
+    expect(result).toEndWith("...")
+  })
+
+  test("multiline collapsed to single line", () => {
+    const sql = "SELECT *\n  FROM table\n  WHERE id = 1"
+    expect(truncateQuery(sql, 100)).toBe("SELECT * FROM table WHERE id = 1")
+  })
+})
+
+describe("truncateQuery: edge cases", () => {
+  test("whitespace-only returns (empty)", () => {
+    expect(truncateQuery("   ", 10)).toBe("(empty)")
+  })
+
+  test("maxLen smaller than 4 hard-truncates without ellipsis", () => {
+    expect(truncateQuery("hello world", 2)).toBe("he")
+    expect(truncateQuery("hello world", 3)).toBe("hel")
+  })
+
+  test("maxLen zero or negative returns empty string", () => {
+    expect(truncateQuery("hello", 0)).toBe("")
+    expect(truncateQuery("hello", -5)).toBe("")
+  })
+})