Test TCP connectivity to a host and port by attempting a three-way handshake, reporting whether the port is open, refused, or timed out.
Try a TCP three-way handshake to host:port and report open, refused or timed out.
Args: host: Host name or IP address. port: TCP port, e.g. 443 for HTTPS, 80 for HTTP, 53 for DNS.
| Name | Required | Description | Default |
|---|---|---|---|
| host | Yes | ||
| port | No |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations exist, so the description carries the full burden. It does disclose the important behavior — a real handshake is attempted and the three possible result states are enumerated — but says nothing about timeout duration, whether results are cached, or what a slow/filtered port yields versus a timed-out one.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
One front-loaded sentence states purpose and outcomes, followed by a compact Args block. No filler and no repetition of schema metadata.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a two-parameter diagnostic tool with no output schema and no annotations, the description covers purpose, both parameters, and the shape of the result. Only timeout/timing expectations are missing, which is a minor gap for an agent deciding whether to wait on the call.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 0%, so the description must compensate, and it does: host is defined as hostname or IP, and port is defined with concrete examples (443/HTTPS, 80/HTTP, 53/DNS) that implicitly clarify it takes a numeric TCP port. It does not restate the 443 default already in the schema, which is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
Names a precise mechanism (TCP three-way handshake) against a precise target (host:port) and states what is reported (open, refused, timed out). That mechanism framing alone separates it from ping (ICMP) and http_check (application layer) in the sibling list, so an agent can pick it without opening the schema.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Usage is only implied: an agent can infer this is the tool for 'is this TCP port reachable'. There is no explicit when-to-use statement, no exclusion, and no mention of the closest alternatives (http_check for a full HTTP request, ping for host liveness).
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.