Get one published heating contractor by its slug.
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": {
"slug": "<slug>"
},
"name": "get_listing"
}
}| Name | Required | Description | Default |
|---|---|---|---|
| slug | Yes | The listing slug. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so the safety profile needs no restating. The description adds one genuine behavioral fact beyond that: only published listings are returned. It does not say whether a missing/unpublished slug yields an error or an empty result, which is the main behavioral gap remaining.
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?
A single ten-word sentence that front-loads the verb and the resource and wastes nothing. Any further length would need to be justified by information not already in the annotations 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 one-parameter, read-only lookup with full annotation coverage and no output schema, the description is nearly sufficient. The only meaningful omission is the outcome of a slug that is missing or unpublished, which matters more here because 'published' is the tool's core filter.
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?
There is a single parameter at 100% schema description coverage, with the pattern and length constraints documented in the schema itself. The phrase 'by its slug' adds no format, source, or normalization detail beyond what the schema already provides, so the 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?
The description uses a specific verb (Get) plus a precise resource (one published heating contractor) and a lookup key (slug). That distinguishes it from the sibling search_listings, which returns collections, without needing to name it explicitly. It stops short of a 5 only because it does not state the inverse scope (e.g., unpublished listings are excluded by design rather than by query).
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: 'by its slug' tells an agent this is a direct lookup once a slug is known, and the word 'published' hints at a visibility constraint. There is no explicit when-to-use statement, no guidance on what to do when no slug is known (search_listings), and no note on behavior when the slug does not resolve.
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.