FIPA Request Whenever Communicative Act Specification


Document title

FIPA Request Whenever Communicative Act Specification

Document number


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Date of this status





Change history


Deprecated by FIPA00037


Line numbering added










2000 Foundation for Intelligent Physical Agents -

Geneva, Switzerland


Use of the technologies described in this specification may infringe patents, copyrights or other intellectual property rights of FIPA Members and non-members. Nothing in this specification should be construed as granting permission to use any of the technologies described. Anyone planning to make use of technology covered by the intellectual property rights of others should first obtain permission from the holder(s) of the rights. FIPA strongly encourages anyone implementing any part of this specification to determine first whether part(s) sought to be implemented are covered by the intellectual property of others, and, if so, to obtain appropriate licenses or other permission from the holder(s) of such intellectual property prior to implementation. This specification is subject to change without notice. Neither FIPA nor any of its Members accept any responsibility whatsoever for damages or liability, direct or consequential, which may result from the use of this specification.


The Foundation for Intelligent Physical Agents (FIPA) is an international organization that is dedicated to promoting the industry of intelligent agents by openly developing specifications supporting interoperability among agents and agent-based applications. This occurs through open collaboration among its member organizations, which are companies and universities that are active in the field of agents. FIPA makes the results of its activities available to all interested parties and intends to contribute its results to the appropriate formal standards bodies.

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The FIPA specifications are developed through direct involvement of the FIPA membership. The status of a specification can be either Preliminary, Experimental, Standard, Deprecated or Obsolete.More detail about the process of specification may be found in the FIPA Procedures for Technical Work. A complete overview of the FIPA specifications and their current status may be found in the FIPA List of Specifications. A list of terms and abbreviations used in the FIPA specifications may be found in the FIPA Glossary.

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1 Scope. 3

2 Request Whenever3

3 References. 3

1         Scope

This document specifies the Request Whenever communicative act that is compliant to [FIPA00037] requirements.


2         Request Whenever


The sender wants the receiver to perform some action as soon as some proposition becomes true and thereafter each time the proposition becomes true again.


A tuple of an action description and a proposition.


Request-whenever allows an agent to inform another agent that a certain action should be performed as soon as a given precondition, expressed as a proposition, becomes true, and that, furthermore, if the proposition should subsequently become false, the action will be repeated as soon as it once more becomes true.


Request-whenever represents a persistent commitment to re-evaluate the given proposition and take action when its value changes. The originating agent may subsequently remove this commitment by performing the cancel action (see [FIPA00041]).


No specific commitment is implied by the specification as to how frequently the proposition is re-evaluated, nor what the lag will be between the proposition becoming true and the action being enacted. Agents who require such specific commitments should negotiate their own agreements prior to submitting the request-when act (see [FIPA00058]).

Formal Model

<i, request-whenever(j, <j, act>, f)>

<i, inform(j, Ii Done(<j, act>, ($e) Enables(e, Bjf)))>

FP: BiaBi (Bifja Uifja)

RE: Bja




a = Ii Done(<j, act>, ($e) Enables(e, Bjf))


Agent i informs j that i intends that j will perform some act whenever some event causes j to believe f.


Agent i tells agent j to notify it whenever the price of widgets rises from less than 50 to more than 50.



:sender i

:receiver j



:sender j

:receiver i


(price widget))

(> (price widget) 50))


3         References

[FIPA00037] FIPA Communicative Act Library Specification. Foundation for Intelligent Physical Agents, 2000.

[FIPA00041] FIPA Cancel Communicative Act Specification. Foundation for Intelligent Physical Agents, 2000.

[FIPA00058] FIPA Request When Communicative Act Specification. Foundation for Intelligent Physical Agents, 2000.