Editing Trivial Service Discovery Protocol

{{Infobox protocol
| name            = Trivial Service Discovery Protocol
| developer       = [[secondtruthLabs]]
| status          = Stable
| first_published = 2025
| latest_version  = 1.0
| transport       = [[wp:User Datagram Protocol|UDP]] Multicast
| default_port    = 7920
| encoding        = [[wp:UTF-8|UTF-8]]
| license         = [[wp:Public domain|Public Domain]]
}}

The '''Trivial Service Discovery Protocol''' ('''TSDP''') is a minimal [[wp:User Datagram Protocol|UDP]] [[wp:IP_multicast|multicast]] protocol for zero-configuration service discovery on local and trusted networks. Developed by [[secondtruthLabs]], it enables automatic discovery of services without requiring a central registry.

== Overview ==

TSDP provides a simple mechanism for services to announce their presence and for clients to discover available services. It is protocol-agnostic and can be used to discover any type of service.

=== Design philosophy ===

* Trivial enough to implement in an afternoon
* Protocol-agnostic discovery
* Multicast-based for zero-config operation
* Secure enough for trusted networks

== Technical specification ==

=== Network configuration ===

{| class="wikitable"
|-
! Parameter !! Value
|-
| Multicast Address || 239.255.83.68
|-
| Port || 7920
|-
| Transport || UDP
|-
| Max Message Size || 512 bytes
|}

=== Message format ===

Messages are single-line, space-separated plain text:

{{Code example
| language = text
| caption  = Message format
| code     = <command> <protocol> <id> <endpoint> [<metadata>]
}}

=== Commands ===

{| class="wikitable"
|-
! Command !! Direction !! Description
|-
| <code>DISCOVER</code> || Client → Network || Request services matching criteria
|-
| <code>ANNOUNCE</code> || Service → Network || Announce service availability
|-
| <code>GOODBYE</code> || Service → Network || Announce service shutdown
|}

=== Examples ===

{{Code example
| language = text
| caption  = Discovery request
| code     = DISCOVER agentfinger * *
}}

{{Code example
| language = text
| caption  = Service announcement
| code     = ANNOUNCE agentfinger myagent tcp://192.168.1.100:7922 capabilities=chat,code
}}

{{Code example
| language = text
| caption  = Shutdown notice
| code     = GOODBYE agentfinger myagent tcp://192.168.1.100:7922
}}

=== Wildcards ===

The <code>*</code> character serves as a wildcard:

* <code>DISCOVER * * *</code> – Discover all services
* <code>DISCOVER agentfinger * *</code> – Discover all AgentFinger services
* <code>DISCOVER * myservice *</code> – Find specific service ID across protocols

=== Metadata ===

Optional key-value pairs appended to messages:

{{Code example
| language = text
| caption  = Metadata format
| code     = key1=value1,key2=value2
}}

Spaces in values must be URL-encoded.

== Protocol support ==

TSDP can discover services for any protocol:

* [[AgentFinger]]
* [[wp:Model_Context_Protocol|MCP]]
* [[wp:Gemini (protocol)|Gemini]]
* [[wp:Gopher (protocol)|Gopher]]
* Custom protocols

== Security considerations ==

TSDP is designed for trusted local networks. It does not provide:

* Authentication
* Encryption
* Access control

Deployments on untrusted networks should use additional security measures such as VPNs or network segmentation.

== See also ==

* [[AgentFinger]]
* [[wp:Multicast DNS]]
* [[wp:Service Location Protocol]]
* [[wp:Simple Service Discovery Protocol]]

== References ==

{{Reflist}}

== External links ==

* [https://github.com/secondtruth/tsdp TSDP Specification Repository]

[[Category:Discovery Protocols]]
[[Category:Multicast Protocols]]
{{stLabs protocol}}