List transit lines

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

Annotations already cover the safety profile (readOnly, openWorld), but the description adds real operational context: exact-match semantics for the number, ~470 total lines, the reported total, and a hard geographic boundary (Attica only, OASA buses/trolleys/metro/tram). It omits pagination/ordering behavior, which is the main remaining unknown.

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 front-loaded sentences: purpose, matching rules, then scoping/caution. Each sentence carries distinct information (verb, match keys, size warning, coverage boundary) with no filler.

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?

With no output schema, the description usefully notes the total is reported, and it bounds scope to Attica. Minor gaps remain around result ordering/pagination, but for a 3-param read-only discovery tool this is essentially complete.

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 67%, so the schema documents query and language but leaves limit bare. The description adds genuine meaning by specifying that matching is exact on the number and supports Greek or Latin names, which is not derivable from the schema alone.

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 ("List or search OASA lines") plus the two match keys (rider-facing number vs. name). This clearly separates it from siblings like find_stops, line_routes and line_schedule, which operate on stops or a single line's structure.

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?

Gives explicit operating guidance: "always pass a query unless you genuinely need a sample", and explains the total-count signal for deciding to narrow. It does not, however, route the agent to a sibling (e.g. line_routes for a line's path once the code is known), so it stops short of full when/when-not/alternatives guidance.

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