Fetch a short excerpt from a specific transport data source using its index, title keyword, or URL fragment. Use it to retrieve source text for summarization or review.
Fetch a short text excerpt from a curated source by index or title keyword.
| Name | Required | Description | Default |
|---|---|---|---|
| max_chars | No | ||
| source_key | Yes | Source index, title keyword, or URL fragment. |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It states the core behavior (fetching a short excerpt) but does not disclose error behavior, truncation details, or what happens when source_key is invalid. This is adequate but minimal.
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 sentence with no filler, front-loading the verb and resource. Every word 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?
For a simple two-parameter fetch tool, the description covers the essential operation and selection method. However, it omits how to discover valid source_key values and what happens on invalid input, and there is no output schema to clarify the return shape.
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?
The schema documents source_key but not max_chars (50% coverage). The description adds context by saying selection is by index or title keyword, but it does not explain that max_chars controls excerpt length. The schema's default/min/max partially compensate.
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 ('Fetch') and a clear resource ('short text excerpt from a curated source'), and specifies the selection method ('by index or title keyword'). This distinguishes it from sibling tools that list sources or search datasets.
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?
No guidance is given about when to choose this tool over siblings such as french_transport_data_get_sources or french_transport_data_search_datasets. The description implies usage for excerpt retrieval but does not state prerequisites or alternatives.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.