Look up an HTTP status code's name, meaning and category. Pure CPU, instant.
Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.
{
"id": 1,
"jsonrpc": "2.0",
"method": "tools/call",
"params": {
"arguments": {
"code": "<code>"
},
"name": "http_status"
}
}| Name | Required | Description | Default |
|---|---|---|---|
| code | Yes | Status code or class such as 4xx |
Changes observed during successful MCP inspections.
Input schema / properties / codeAdded value: +{
+ "description": "Status code or class such as 4xx",
+ "type": "string"
+}Input schema / requiredAdded value: +[
+ "code"
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden and does add useful behavioral context: 'Pure CPU, instant' signals a deterministic, offline, zero-cost call with no network or auth requirements. However, it omits what happens on an invalid or unknown code (error vs. empty result) and whether partial classes like '4xx' return a list, which matters for correct invocation.
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?
Two short sentences, zero waste, with what-it-does front-loaded and the operational note second. Nothing redundant with the name or schema.
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 trivial one-parameter lookup with no output schema, the description covers both the input interpretation and the returned fields (name, meaning, category) plus cost characteristics. The only real gap is unsupported/edge-case input behavior.
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 100% and the single parameter already documents that it accepts a code or a class such as '4xx', so the description adds no meaning beyond the schema; baseline 3 applies.
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?
States a specific verb and resource ('look up an HTTP status code's name, meaning and category'), which immediately distinguishes it from the fuzzy sibling status_check or generic lookup tools. An agent can identify the function 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 strongly implied by the narrow domain — an agent knows to call this when it needs to interpret a code like 404 — but there is no explicit when-to-use/when-not guidance and no mention of the similarly named sibling status_check, which could confuse selection.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.