# Opus 4.8 > Source: > Published: 2026-06-04 00:00:00+00:00 Opus 4.8 now powers Amp's `smart` mode, replacing Opus 4.7. It is a better coding agent than Opus 4.7: more faithful to the prompt, tighter in the changes it makes, and better at checking its own work. In our internal evals it solved **62%** of tasks, up from 4.7's **52%**. Opus 4.7 was already strong on hard, multi-file work, and Opus 4.8 keeps that. What changes is how it gets there: with fewer wasted steps and more self-checking. The clearest difference is restraint and verification. Opus 4.7 can sometimes over-engineer, reaching for a more elaborate solution than the task needs. It also verifies its own work less, occasionally moving on even when a command's output is already warning that something is off. Opus 4.8 makes a more focused change that solves the specific intended task, then checks itself. It leans on a tighter write→test loop, often spinning up a quick script, test, or skill to confirm the change works before proceeding. In our evals it ran tests and code 15% more per task than 4.7. That restraint is easiest to see on hard tasks. On everyday work the two make a similar number of tool calls. The harder a task gets, the tighter 4.8 stays, just where 4.7 tends to run long and fail more often. Opus 4.8 is noticeably better at using its tools and sub-agents without being told to. When a task needs outside context, it actually calls `librarian` instead of inferring a library's behavior from the local code. Across our eval it reached for it 14 times, versus once for Opus 4.7. It also reaches for a repo's skills more often to verify its work, for example by driving the browser or the CLI, rather than just assuming the change worked. When it edits, it leans on `edit_file` for surgical, in-place changes rather than rewriting whole files with `create_file` . In our evals 79% of its file edits go through `edit_file` , up from 63% on Opus 4.7. We dropped the `Read` tool from `smart` . Opus 4.8 is good enough at reading files straight from the shell with `cat` , `rg` , `sed` , and `nl` . It parallelizes those reads when it needs several files at once. Opus 4.8 has a fast mode at roughly 2.5× the speed. It now costs 2× base tokens, down from 6× on 4.7—3× cheaper. Toggle fast mode for a thread from the CLI command palette (`Ctrl+O`) → `speed: use fast` . Opus 4.8 stays close to what you ask, changes less to get there, and checks its own work. A few habits make it shine: