Exhibit 10.1

AMENDED AND RESTATED

SEVERANCE BENEFITS AGREEMENT

This AMENDED AND RESTATED SEVERANCE BENEFITS AGREEMENT (the “Agreement”), made
this 20 day of September, 2007, is entered into by and between Gensym
Corporation, a Delaware corporation (the “Company”), and Stephen D. Allison (the
“Executive”) (together, the “parties”).

WHEREAS, the Company wishes to provide the Executive with severance benefits in
the event of the Executive’s separation from the Company under the circumstances
provided for herein;

WHEREAS, the Company and the Executive are parties to that certain Severance
Benefits Agreement, dated June 7, 2007 (the “Original Agreement”); and

WHEREAS, the Company and the Executive desire to amend and restate the Original
Agreement in its entirety as provided herein.

NOW, THEREFORE, in consideration of the Executive’s continued employment by the
Company as Vice President, Finance and Chief Financial Officer and other good
and valuable consideration, the sufficiency of which is hereby acknowledged, the
parties agree to amend and restate the Original Agreement, which shall be
superseded in its entirety and shall be of no further force and effect, as
follows:

 

  1. Separation and Severance.

 

  a. Separation. The Executive acknowledges and agrees that his employment with
the Company shall terminate on the earlier to occur of (1) the date of the
closing of the merger contemplated by that certain Agreement and Plan of Merger,
dated August 13, 2007 and as the same may be amended from time to time, among
the Company, Versata Enterprises, Inc. and GN Acquisition, Inc., pursuant to
which the Company will be acquired and (2) February 28, 2008 (such earlier date,
the “Separation Date”). Effective as of the Separation Date, the Executive’s
employment with the Company shall terminate and the Executive shall cease to
have any power or authority to act either as an employee or an officer of the
Company, or any of its affiliates.

 

  b. Eligibility for Severance Benefits. In the event the Executive continues to
work from the date of this Agreement through the Separation Date and is not
sooner terminated by the Company for cause, as that term is defined in Paragraph
3 below, the Executive shall be entitled to the following severance benefits.

 

  i.

Severance Pay and Medical Benefits Continuation. The Company shall pay the
Executive Severance Pay equal to $723.08 (seven hundred and

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twenty-three dollars and eight cents) multiplied by the number of business days
(Monday through Friday, including Company holidays) from the Separation Date
until February 28, 2008, less all applicable state and federal taxes and other
applicable withholdings (the “Severance Pay”). The Severance Pay will be paid to
the Executive in installments in accordance with the Company’s regular payroll
practices but such payments shall not commence until after the Severance
Agreement, defined in section 5 below, becomes biding upon him. In addition,
until March 1, 2008 (the “Medical Benefits Termination Date”), the Company shall
continue to provide and pay for the Executive’s current medical insurance
coverage under the Company’s group current medical insurance plan.

 

  ii. COBRA Benefits. Effective as of the Medical Benefits Termination Date, the
Executive shall be considered to have elected to continue receiving group
medical insurance pursuant to the federal “COBRA” law, 29 U.S.C. §1161 et seq.
The Executive shall pay all premium costs required to maintain such group
medical insurance for as long as, and to the extent that, the Executive remains
eligible for COBRA continuation and elects to continue such COBRA continuation.

 

  iii. Bonus. Following the Separation Date, the Executive shall receive a bonus
payment equal to twenty percent (20%) of the regular base salary he earned
between September 1, 2007 and the Separation Date, less applicable taxes and
withholdings. Such bonus payment shall be paid with the first installment of the
Severance Pay.

 

  2. Severance Benefits Unavailable. The Executive shall not be entitled to any
severance benefits if the Executive’s employment with the Company is ended under
any of the following circumstances:

 

  a. Termination for Cause. The Executive’s employment is terminated by the
Company for cause, as that term is defined in Paragraph 3 below;

 

  b. Termination for Death or Disability. The Executive’s employment is
terminated as a result of the Executive’s death, or because of the Executive’s
physical or mental disability which renders the Executive unable to perform the
essential functions of the Executive’s job for a period of more than 90 days,
whether or not consecutive, during any 360-day period. A determination of
disability shall be made by a physician satisfactory to both the Executive and
the Company, provided that if the Executive and the Company do not agree on a
physician, the Executive and the Company shall each select a physician and these
two together shall select a third physician, whose determination as to
disability shall be binding on all parties; or

 

  c. Resignation. The Executive provides the Company with oral or written notice
of resignation from employment with the Company.

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  3. Cause. For purposes of this Agreement, “cause” for termination shall be
deemed to exist only upon (a) a good faith finding by the Board of the material
failure of the Executive to perform his assigned duties for the Company,
provided you have not cured such deficiencies within thirty days notice of any
such deficiency, (b) a good faith finding by the Board of the Executive’s
dishonesty, gross negligence or misconduct in the carrying out of these duties,
or (c) the indictment of the Executive for, or the conviction of the Executive
of, or the entry of a pleading of guilty or nolo contendere by the Executive to,
any crime involving moral turpitude or any felony.

 

  4. Employment at Will. Nothing in this Agreement may be construed or
interpreted as an agreement, either expressed or implied, to employ the
Executive for any stated term, and shall in no way alter the at-will nature of
the Executive’s employment with the Company, allowing both the Executive and the
Company to terminate the employment relationship with or without cause at any
time without notice.

 

  5. Release. The obligation of the Company to make the payments and provide the
benefits to the Executive under Section 1(b)(i) through Section 1(b)(iii) of
this Agreement is conditioned upon the Executive signing and not revoking a
severance agreement and release prepared by and provided by the Company (the
“Severance Agreement”) and abiding by the provisions of the Severance Agreement.
Among other things, the Severance Agreement shall contain a confidentiality
provision, a non-disparagement provision, and a release and waiver of any and
all claims that the Executive or the Executive’s representatives may have
against the Company, its affiliates and/or representatives, and shall release
those entities and persons from any liability for such claims including, but not
limited to, all claims related to the Executive’s employment.

 

  6. Section 409A. It is intended that all payments made under the terms of
Sections 1(a) and 1(b) come within exceptions to Section 409A of the Internal
Revenue Code of 1986, as amended (“Section 409A”). This Agreement shall be
interpreted and administered in accordance with that intention. However, if any
amount payable under this Agreement is determined to be subject to Section 409A
then such payments shall be administered in accordance with Section 409A;
provided that the Company shall not be liable for any failures under this
section that result in the payment of any taxes or other amounts due under the
terms of Section 409A. To the extent any amount subject to Section 409A is to be
paid or provided to the Executive in connection with a separation from service
at a time when he is considered a specified employee within the meaning of
Section 409A then such payment shall not be made until the date that is six
months and one day following such separation from service, or in a lump sum upon
his earlier death.

 

  7. Entire Agreement. This Agreement contains and constitutes the entire
understanding and agreement between the parties hereto with respect to severance
benefits and cancels all previous oral and written negotiations, agreements,
commitments, understandings and writings in connection therewith.

 

  8.

Amendment. This Agreement shall be binding upon the parties and may not be
abandoned, supplemented, changed or modified in any manner, orally or otherwise,
except by an instrument in writing of concurrent of subsequent date signed by a
duly

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authorized representative of the parties hereto. This Agreement is binding upon
and shall inure to the benefits of the parties and their respective agents,
assigns, heirs, executors, successors and administrators.

 

  9. Validity. Should any provision of this Agreement be declared or be
determined by any court of competent jurisdiction to be illegal, invalid or
unenforceable, the validity of the remaining parts, terms, or provisions shall
not be affected thereby and said illegal, invalid or unenforceable part, term or
provision shall be deemed not to be a part of this Agreement.

 

  10. Applicable Law. This Agreement shall be governed by and interpreted under
the laws of the Commonwealth of Massachusetts, without regard to conflict of
laws provisions, and is binding upon and shall inure to the benefit of the
parties and their respective agents, assigns, heirs, executors, successors and
administrators. The Executive hereby irrevocably submits to, acknowledges and
recognizes the jurisdiction of the state and federal courts of Massachusetts
(which courts, together with all applicable appellate courts, for purposes of
this Agreement, are the only courts of competent jurisdiction) over any suit,
action, or other proceeding arising out of, under or in connection with this
Agreement.

 

  11. Voluntary Assent. The Executive affirms that no other promises or
agreements of any kind have been made to or with him by any person or entity
whatsoever to cause him to sign this Agreement, and that he fully understands
the meaning and intent of this Agreement. The Executive states and represents
that he has had an opportunity to fully discuss and review the terms of this
Agreement with any attorney. The Executive further states and represents that he
has carefully read this Agreement, understands the contents herein, freely and
voluntarily assents to all of the terms and conditions hereof, and signs his
name of his own free act.

 

  12. Counterparts. This Agreement may be executed in two (2) signature
counterparts, each of which shall constitute an original, but all of which taken
together shall constitute but one and the same instrument.

IN WITNESS WHEREOF, all parties have set their hand and seal to this Agreement
as of the date written above.

 

GENSYM CORPORATION

/s/ ROBERT B. ASHTON

Robert B. Ashton Chief Executive Officer

/s/ STEPHEN D. ALLISON

Stephen D. Allison