Preview the first rows of a CSV or JSON file on dados.gov.pt to check its format and sample data before downloading the full file.
First rows of a CSV or JSON file hosted on dados.gov.pt (reads at most 512 KB).
Args: url: a resource url from open_data_dataset (must be on dados.gov.pt). rows: how many rows to return (1-100).
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | ||
| rows | No |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v0.1.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It usefully discloses the 512 KB read limit and the 1-100 row constraint, but omits error behavior for oversized or unsupported files and does not clarify whether the full file is fetched or truncated.
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?
The description is short and front-loaded: the first sentence states what it does and the main constraint, followed by concise parameter notes. Every sentence earns its place.
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?
An output schema exists, so return-value explanation is unnecessary. For a simple two-parameter read preview, the description covers format, host restriction, size cap, and row limits. Error handling on unsupported or oversized files is the main omission.
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. It explains that url must be a resource URL from open_data_dataset and hosted on dados.gov.pt, and that rows must be between 1 and 100. It does not mention the default of 20, but otherwise adds real meaning beyond the bare schema.
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 states a specific operation: return the first rows of a CSV or JSON file hosted on dados.gov.pt. It also ties the url input to open_data_dataset, which distinguishes it from sibling tools. It is clear, though it does not explicitly frame itself as a preview-before-download step.
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 implied through 'a resource url from open_data_dataset', which tells the agent this follows dataset discovery. However, there is no explicit when-to-use/when-not-to-use guidance and no named alternative for full downloads.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.