Routes serving a stop

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: the data is scheduled rather than live, and coverage is limited to greater Athens OASA modes. It does not mention result ordering or volume limits, keeping it short of a 5.

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?

Three sentences, front-loaded with the purpose, then the live-vs-scheduled caveat, then the coverage boundary. No filler and each sentence carries distinct information.

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?

No output schema exists, but the description conveys what comes back (lines/routes serving the stop) and what the data represents (schedule, not real-time). The mode/geography limit is stated, which is the main completeness risk. Minor gap: no mention of result shape or pagination for a potentially long list.

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 coverage is 100%, so all three parameters are already documented in the schema. The description reinforces the 'stop' parameter's accepted forms (name in either script or exact stop_code) but says nothing about 'language' or 'include_hidden', 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?

States a specific verb and resource ('which OASA lines and routes call at a given stop') and frames the user intent ('what can I catch from here'), which cleanly separates it from find_stops and stop_arrivals. The scope (Attica, OASA buses/trolleys/metro/tram) further pins down what it returns.

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?

Explicitly routes the agent away from the wrong sibling: 'This is scheduled network data, not live: use stop_arrivals for actual waiting times.' It also states the geographic/mode boundary, so an agent knows when this tool will not help.

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