Mainframe & COBOL code analysis
Mainframe & COBOL Code Analysis Platform
Tweezr builds a deterministic map of your COBOL estate - every program, job, field, dependency and business rule - then answers questions about it with citations to the exact program, paragraph and field. On-prem, and nothing leaves your perimeter.
Every artifact the core actually runs on.
Tweezr parses COBOL, JCL, copybooks and the surrounding artifacts into one navigable graph - an explainable model of how the system behaves, not a probabilistic guess.
Programs and call graphs
Every COBOL, PL/I and Assembler program resolved into a traversable call graph - the legacy "central nervous system", with certainty about how everything connects.
- COBOL
- PL/I
- Assembler
- CICS
- IMS-TM
JCL, batch and scheduling
JCL jobs and steps mapped to the programs and datasets they run. Schedulers such as Control-M, CA-7 and IBM TWS are mapped on-demand per engagement.
- JCL
- Control-M*
- CA-7*
- IBM TWS*
Copybooks and schemas
Copybooks, DCLGEN and screen maps resolved to every program that includes them, so a layout change shows its full reach.
- Copybook
- DCLGEN
- BMS
- MFS
Fields and data lineage
Reverse-engineer and path-trace each field of the data schema - a value traced end to end across programs, files and databases.
- VSAM
- DB2 z/OS
- IMS-DB
- Sequential files
Business rules
Cross-program business-rule extraction: the "what" and "why" buried in the code, organized and editable, each rule cited back to its source.
The estate around the code
IBM MQ in full; change management, file transfer and security tooling (Endevor, Connect:Direct, RACF and more) on-demand - because real lineage reads all of it.
- IBM MQ
- Endevor*
- Connect:Direct*
- RACF*
* On-demand: calibrated per engagement - see the full coverage matrix below.
Know what breaks before anything changes.
Analysis is system-level and cited: every answer points back to the exact program, paragraph and field it came from - re-runnable, with no invented dependencies.
Blast-radius impact analysis
See every program, job and data structure a proposed change touches before a line of code moves - explainable "what breaks if…" answers, not a list of text matches.
Citations to source
Answers are cited to the exact program, paragraph and field, and re-runnable - so an engineer can trust the answer and a manager can sign off.
Root cause by evidence
Trace incidents precisely by evidence, not tribal memory. Root cause analysis takes less than 10 minutes; process archaeology that took a week, under 45.
Batch window optimization
Combine SMF records with extracted process flows to see the nightly batch window as it really runs, and find what can be shortened, reordered or retired.
Grounding for your coding agents
Available as an MCP server: Claude Code, Cursor, GitHub Copilot or any MCP-compatible client can query the map directly, so every suggestion is anchored in verified, system-wide facts.
Tweezr vs. AI coding agents for COBOL →Onboarding in under 30 minutes
New developers get productive on a system no one fully remembers via a natural-language interface - in less than 30 minutes.
COBOL first - and everything legacy around it.
Full coverage on z/OS - TP monitors, batch languages, data and screen layers - plus the platforms your mainframe transactions land on.
Legacy platforms
Mainframe · z/OS
The mainframe, fully mapped
IBM z-Series - the heart of most banking back-offices. Full coverage across TP monitors, batch languages, data and screen layers. Every program, copybook, and queue resolved into one navigable graph.
TP / online monitors
Batch languages
Data
Schema / screens
Example lineage trace
From a CICS green screen, follow a payment through a COBOL transaction, into DB2 z/OS, and out via MQ to a Java microservice - every hop with attested provenance.
Generic LLMs guess at COBOL because they've never seen the calling graph. Tweezr reads it.
Where the legacy lands →
Cross-platform
Runs where your code already lives.
Zero customer data or PII leaves your environment - whichever option you choose.
On-premises
Tweezr operates fully on-premise within your bank's landing zone. The deterministic preprocessing runs on a single machine with no external connectivity required, using your existing AI licenses.
IBM LinuxONE & Linux on IBM Z
Available on and supported on IBM LinuxONE and Linux on IBM Z: ingestion, static analysis, the dependency graph and local model inference run as a native s390x build - not emulation. Inference runs locally on IFLs, with no outbound calls.
Tweezr on IBM LinuxONE →Your own cloud
Run Tweezr inside your own cloud tenancy - your code never leaves your perimeter. Or start in our hosted playground with sample code and zero data sharing.
Four ways to try Tweezr →COBOL code analysis, answered
Common questions about mapping and analysing a mainframe estate with Tweezr.
A deterministic blueprint built from your code, inside your perimeter - pilot to first trusted answer in 2 weeks.