COBOL functions that answer questions about text

A copybook and called programs over the C library, for GnuCOBOL.

Install

Channel	Note
`thinkthen-cobol-VERSION-TARGET.tar.gz`	The copybook and the called programs, from each release.
`thinkthen-c-VERSION-TARGET.tar.gz`	The C library it calls, from the same release.

Set THINKTHEN_API_KEY in the environment.

A first call

identification division.
program-id. first-call.
environment division.
configuration section.
repository. function all intrinsic.
data division.
working-storage section.
copy "thinkthen.cpy".
01 engine usage pointer.
01 question pic x(200).
01 question-length usage binary-double unsigned.
01 evidence pic x(200).
01 evidence-length usage binary-double unsigned.
procedure division.
    call "thinkthen_engine_new" returning engine

    move "Does the customer ask for a refund?"
        to question
    move "Please refund my order. It arrived broken."
        to evidence
    perform ask-it
    if not outcome-yes
        stop run returning 1
    end-if

    move '{"decide": "Does the customer ask ' &
        'for a refund?", "threshold": "0.2:0.8"}'
        to question
    move "I want to send this back." to evidence
    perform ask-it
    if not outcome-not-sure
        stop run returning 1
    end-if
    stop run returning 0.

ask-it.
    move length(trim(question trailing))
        to question-length
    move length(trim(evidence trailing))
        to evidence-length
    call "TT-DECIDE" using engine
        question question-length
        evidence evidence-length
        tt-deadline-ms tt-answer tt-facts tt-failure.

Build and run it beside the unpacked archives, thinkthen-c/ and thinkthen-cobol/

cobc -x -free \
    -fstatic-call -fno-gen-c-decl-static-call \
    -I thinkthen-cobol/copybooks \
    -A "-include $PWD/thinkthen-c/include/thinkthen.h \
    -Wno-incompatible-pointer-types \
    -Wno-implicit-function-declaration" \
    -o first-call first-call.cob \
    thinkthen-cobol/src/tt_decide.cob \
    thinkthen-cobol/src/tt_error.cob \
    -L thinkthen-c/lib -lthinkthen \
    -Q "-Wl,-rpath,$PWD/thinkthen-c/lib"
./first-call

Not sure comes back as outcome-not-sure. Branch on it and send those cases to a person.

Run facts

TT-DECIDE fills tt-facts with this call's run facts as JSON text. TT-JSON-MEMBER reads one member.

Errors

tt-failure holds the kind as a code from 1 to 6, the retry flag and the message. Its level-88 names, such as failure-backend, test each kind.

Settings and recording

TT-ENGINE-NEW takes the settings as JSON. "record" writes a recording to a folder. "replay" answers from that recording with no connection. The Settings page lists every setting.

Jev, Liquid d1 and Ollama from COBOL

COBOL reads its backend from the environment. Set THINKTHEN_BACKEND to the name below. Set the backend's key variable in the shell, and the same sample asks that backend.

Backend	Name	Key variable
TypeSafe Jev	`typesafe`	`TYPESAFE_API_KEY`
Liquid d1	`liquid`	`LIQUIDAI_API_KEY`, then `LIQUID_API_KEY`
Ollama	`ollama`	`OLLAMA_API_KEY`. A local address needs no key.

Ask TypeSafe Jev.

export THINKTHEN_BACKEND=typesafe
export TYPESAFE_API_KEY=...

Ask Liquid d1.

export THINKTHEN_BACKEND=liquid
export LIQUIDAI_API_KEY=...

Ask Ollama. This block names a second port, 11535, as the site's runs do. On the default port, leave THINKTHEN_BASE_URL out.

export THINKTHEN_BACKEND=ollama
export THINKTHEN_BASE_URL=http://localhost:11535/v1

identification division.
program-id. backends.
environment division.
configuration section.
repository. function all intrinsic.
data division.
working-storage section.
copy "thinkthen.cpy".
01 engine usage pointer.
01 refund-question pic x(200)
    value "Does the customer ask for a refund?".
01 question pic x(200).
01 question-length usage binary-double unsigned.
01 evidence pic x(200).
01 evidence-length usage binary-double unsigned.
procedure division.
    call "thinkthen_engine_new" returning engine

    move "Please refund my order. It arrived broken."
        to evidence
    perform ask-it
    if not outcome-yes
        stop run returning 1
    end-if

    move "Thanks for the quick help yesterday!"
        to evidence
    perform ask-it
    if not outcome-no
        stop run returning 1
    end-if
    stop run returning 0.

ask-it.
    move refund-question to question
    move length(trim(question trailing))
        to question-length
    move length(trim(evidence trailing))
        to evidence-length
    call "TT-DECIDE" using engine
        question question-length
        evidence evidence-length
        tt-deadline-ms tt-answer tt-facts tt-failure.

Build and run it beside the unpacked archives, thinkthen-c/ and thinkthen-cobol/

cobc -x -free \
    -fstatic-call -fno-gen-c-decl-static-call \
    -I thinkthen-cobol/copybooks \
    -A "-include $PWD/thinkthen-c/include/thinkthen.h \
    -Wno-incompatible-pointer-types \
    -Wno-implicit-function-declaration" \
    -o backends backends.cob \
    thinkthen-cobol/src/tt_decide.cob \
    thinkthen-cobol/src/tt_error.cob \
    -L thinkthen-c/lib -lthinkthen \
    -Q "-Wl,-rpath,$PWD/thinkthen-c/lib"
./backends

The configuration file's backend names a default backend for every run. The Configuration page shows the file.

OpenAI Decisions API from COBOL

OpenAI announced its Decisions API on 2026-09-29 in its DevDay 2026 recap. OpenAI has published no address, schema or price, so ThinkThen cannot call it. The OpenAI Decisions API page says what ThinkThen knows.

What is different in COBOL

Compile the programs you call from src/ with your own, as the build line does with TT-DECIDE.
The copybook names no, yes and not sure as level-88 conditions, so if outcome-yes reads the answer.
TT-DECIDE writes into the question buffer, so set the question again before each call.

On GitHub: github.com/botassembly/thinkthen