# Work modes What an agent may do at a customer is not a pile of loose checkboxes. It is one chosen **work mode** on the task. Whoever creates the task chooses the mode. The platform enforces it on every tool call. ## The modes | Mode | In one sentence | What the source needs for it | | --- | --- | --- | | **Look only** | Read metadata, counts and history. Proves nothing, touches nothing. | A read-only login with permission to read metadata and statistics. | | **Measure on the source** | On top of that, the estimated execution plan and the real execution counters, without running anything. | Extra permission to show plans. | | **Prove on a disposable copy** | Read on the source, and run and measure the proposal in a copy. | A copy of (part of) the data, with the content the customer allows. | A mode is a combination of four questions: 1. **Where** is the work done? 2. **On what**: the source itself or a disposable copy? 3. **What is in the copy**: synthetic data, synthetic data shaped to the real statistics, or real data? 4. **What is allowed**: read only, read plus measure, free SQL on the copy, or write on the source? No two modes give the same answer to those four questions. ## Why modes? A work mode makes visible what a task costs and what it risks. "Look only" needs a read-only login and cannot break anything. "Measure on the source" needs extra permissions, and those extra permissions are exactly why it is a separate mode. "Prove on a disposable copy" lets an agent really run its proposal, but never on the real database. :::tip Which mode do I choose? - A question about structure, quality or history: **look only**. - A question about why a query is slow: **measure on the source**. - A proposal for a new index, a rewritten procedure or a new view: **prove on a disposable copy**. ::: ## Who checks what - **On creation** the platform refuses a mode that does not exist, or a mode the source does not support. The refusal comes before anything runs that costs money. - **On every tool call** the tool gateway checks what the tool needs from the mode. A measuring tool in a task on "look only" is refused. The refusal names the task's mode, not the other tools that would have been allowed. - **On screen** all modes are listed with one sentence of explanation. ## Monitors only look A [monitor](/concepten/monitors) always runs in "look only". A periodic check reads and judges, but proves and changes nothing. ## And writing on the source? Writing on the real source is not a work mode but a permission per source. An agent can propose a script. A human approves it, and only then is it run. Without that permission on the source nothing happens, not even after approval. ## Example A BI developer wants to know whether a new index makes the nightly load faster. 1. She chooses **prove on a disposable copy**. 2. The agent reads the structure and statistics on the source, and creates a copy. 3. It runs the procedure in the copy, measures the run time, adds the index and measures again. 4. The platform compares both measurements and gives a verdict. 5. The developer sees the result and decides herself whether the index goes to production. More about the copy: [The verification sandbox](/concepten/sandbox). ## See also - [Data access per source](/concepten/datatoegang) - [The verification sandbox](/concepten/sandbox)