Agents now write enough code that review is the bottleneck. The launches that address this fall into two groups: ones that limit what an agent is allowed to do before it acts, and ones that check what it actually did afterwards. Both are cheaper than reading every diff yourself. Here are nine recent ones.
Limit the blast radius first
Alter is privileged access management rebuilt for agents. Provider credentials live in a vault rather than in the model's context, a default-deny policy engine evaluates each request down to the individual parameter, every agent gets its own identity with delegation and IdP integration, and sensitive calls wait for a named human. Because policy is evaluated per call, "the agent may read repositories" becomes a scope check rather than a suggestion, and every decision lands in a tamper-evident audit record.
The same logic applies to the servers you let an agent install. MCP Census checks the public evidence for an MCP server and returns PASS, REVIEW, BLOCK or UNKNOWN, asking the questions that matter: is this the vendor's own server or a lookalike, is it still maintained, and what can you open as proof. It is explicit that it is a first gate and not a malware scan, and it serves the same facts over plain HTTP and over MCP, so your own agent can audit a whole `.mcp.json` with one call before it touches any of them.
Check the running app, not the page text
A green test run and a working page are not the same thing. IronBee Express is a browser agent that verifies whether your app really did what the page claims, and finds the root cause when it did not. It drives real flows such as logging in, adding to cart and checking out, and spends deeper reasoning only on the steps that need it. Connect the hosted IronBee platform and each run is kept with its video, plus the backend traces and logs behind the verdict.
Read the whole diff in one place
Reviewing an agent's work usually means clicking through files one at a time. Twain puts every file from a Git diff into one sequential view, with a fast file tree, scrolling minimaps, tree-sitter highlighting and search across all modified files. You can show changed parts only or full files, revealing unchanged context granularly, and you can comment on sets of changes and lines. Those comments are readable from a CLI, so an agent can read them and add its own, which turns review into something both sides participate in. It does not merge, does not do three-way comparisons and does not edit files, which is arguably the point.
Test the experience, not the feature
Your docs, CLI and MCP server may be correct and still unusable by an agent. Gauge CLI is an open-source tool for hillclimbing agent experience: it runs real coding agents against your Skills, CLI, SDK, MCP server, API or docs and captures where they get stuck. Typical findings include an interactive command that blocks an agent, a deprecated API pattern it keeps reaching for, a Skill that never triggers, or a confidently stated limitation that does not exist. Your own agent can then test a proposed fix before you publish it, and the whole loop runs locally in Docker with the subscriptions or API keys you already have.
Know when to stop
Long agent runs fail in a particular way: they hit a usage ceiling partway through an edit and you lose the context. Fuel Gauge is an unofficial Claude Code plugin that reads the five-hour window, the weekly window and the context fill from the responses your session already receives, so it costs no extra API calls. Every message carries one line with the remaining quota and reset time, a small gauge sits above the input, and it pulls a hard stop at 95% so work ends at a clean point instead of mid-edit.
Two edge cases worth knowing about
Not every launch in this group is comfortable. Refuseless is a hosted, OpenAI-compatible inference API serving open-weight GLM checkpoints with the refusal direction removed from the weights, priced per million tokens with no prompt retention after the response. It is aimed at security teams, and it is a real example of the governance gap that access-control tools like Alter exist to close.
Jaynshare is a self-hosted Rust proxy that routes each prompt to whichever Claude or Codex account in a pool still has quota, so you can keep working when your own account is rate limited. It is MIT licensed and well documented, and its own README warns that pooling Claude subscriptions conflicts with Anthropic's terms and can get every account involved suspended. Read that warning before you deploy it anywhere that matters.
Making the output readable
One launch in this batch is about the review surface itself. Answer Me With HTML is an agent skill that answers hard questions with a single readable HTML page instead of a wall of terminal text, with diagrams where they help. It works across Claude Code, Codex, Cursor, OpenCode, Pi and DeepSeek Harness, and because the model writes a compact page rather than hand-writing the HTML, it uses roughly an eighth of the tokens a full formatted answer would need.
The pattern
Every one of these tools moves a check earlier: policy before the call, provenance before the install, verification before the merge, a stop before the cut-off. Agents are fast enough now that the cost of being wrong is mostly the cost of not noticing.
