stl_snapshot_fetch

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description discloses important side effects and behavior: it performs network downloads, uses conditional requests with 304 responses, and can take a few seconds due to file sizes. This goes beyond the annotations, which already indicate readOnly=false and idempotent=false.

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 concise and well-structured: a clear first sentence, then additional relevant details about conditional requests and expected size/time, followed by the argument explanations. No unnecessary wording.

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?

The description gives enough context for invocation, including source and force semantics and performance characteristics. It mentions the return field 'unchanged=true' but leaves other return details to the output schema, which is acceptable given the tool's simplicity.

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 has no parameter descriptions, but the description fully compensates by listing the valid source values ('metro_gtfs', 'metro_rt_trips', 'metro_rt_vehicles', 'metro_rt_alerts') and explaining that force bypasses the conditional-request cache.

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 action ('Download a feed from the network into the local snapshot store') and clearly distinguishes this from sibling tools like stl_snapshot_list and stl_snapshot_sources by focusing on the fetch/refresh action.

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?

The description gives clear context for when to use the tool: to download a feed into the snapshot store. It explains the source options and the force flag, though it does not explicitly name alternative sibling tools or state when not to use them.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.