ATDL
Tools → ATDL is the current FIXatdl Inspector. Library → ATDL lists simulator scenarios and tenant files, then opens a selected file in that inspector.
Inspect a file
Paste or load a FIXatdl 1.1 strategies file in Tools → ATDL, then select Inspect. The tool shows the rendered form, state rules, source XML, FIX preview, and any schema errors. Inspection runs server-side and does not save the document.
The retired /atdl route points users to the current tools workflow; bookmarks should move to /tools/atdl.
Tenant library
In Library → ATDL, select Upload to library to enter a name and upload or paste XML. The library accepts names of 1 to 64 letters, digits, dots, dashes, or underscores, and XML files up to 3 MB. It validates the submitted document before saving it.
The list separates Simulator Scenarios from Your ATDL Files. Filter by file name, select a name to open it in the inspector, or delete a tenant file after confirmation. Built-in scenarios are not deletable from this screen.
The Library screen does not provide an in-place editor, a preview record, or an update action. To revise a tenant document, inspect the revised XML, then upload it under an available file name.
Safe change sequence
- Inspect the XML and resolve schema errors.
- Check every strategy and rendered control.
- Exercise enum choices, boundary values, and state-rule branches.
- Compare the FIX preview with the broker contract.
- Upload the validated document to Library → ATDL.
Deleting a tenant file removes it from the library. Preserve the source document and keep file names, strategy names, parameter identifiers, and FIX mappings stable when external systems depend on them.
For the document shape and control convention, see Writing an ATDL strategy.
Retune a session over its FIX connection
The four built-in scenarios under Simulator Scenarios are not only documents to inspect. Their parameters are the simulator's own behaviour settings, so a connected counterparty can select one and send it as a strategy order to change how the session behaves, without opening this UI or holding a login.
This is off by default. Enable Allow retuning over the FIX session in Sim Config → Default behaviour on the session that should accept it. While it is on, anyone who can log on to that session can change its settings, so leave it off unless a test needs it.
What the sender sends
An ordinary NewOrderSingle carrying the strategy's parameters, in either form:
- StrategyParametersGrp, tag 957, with a
_FpSimSchema/SimConfigpair marking it as a command. - Per-parameter tags, StrategyIdentifier 5001 plus the scenario's own fixTags 5100 to 5113. This is what an ATDL host such as an EMS sends.
Both reach the same settings. The session's FIX dictionary must define those tags, or the message is refused before the simulator sees it.
What comes back
An ExecutionReport with the text SimConfig patch applied. The order is consumed as a command and never simulated, so there is no fill to wait for. Submit an ordinary order afterwards to see the new behaviour.
If any value fails validation the whole change is refused, with SimConfig: invalid parameter <name> and OrdRejReason 0. Nothing is partly applied.
Parameters
ResponseTimeMin and ResponseTimeMax, AcceptPercent, ErrorPercent, FillCountMin and FillCountMax, FillStaggerTimeMin and FillStaggerTimeMax, FillTimeMin and FillTimeMax, AutoAcknowledge, AutoAcceptCancels, AutoAcceptReplaces, RejectInboundOrders.
Percentages are 0.0 to 1.0. The four switches take Y or N. Omit a parameter to leave it as it is.
Send both halves of a range together. A minimum on its own is checked against the maximum already on the session, so raising FillCountMin to 3 without also raising FillCountMax is refused.
Message rate, reject pool, allowed security ID sources and dictionary are not changeable this way; use Sim Config.
Updated 2026-09-14 · Edit on GitHub