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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds the useful behavioral detail that results are grouped by direction with headsign and stop order, but says nothing about error behavior for unknown routes or how kind disambiguation affects the result.

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 front-loaded sentence with no filler; the return structure is stated first and the qualifier second. Minor cost: 'TTC' is unexplained, though the title clarifies the Tbilisi context.

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 a full output schema, complete parameter descriptions, and read-only annotations, the description only needs to state scope and return shape — which it does. Missing only edge-case behavior (unknown route, ambiguous route number across kinds), which is a small gap for a simple lookup.

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 100%, so route number/id, kind, and language are already documented in the schema. The description mentions no parameters at all, adding no meaning beyond the structured fields — 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 ('Returns a route of the TTC') and specifies the payload shape: each direction with its headsign and ordered stops. That clearly separates it from search/list siblings like transit_search_routes, though it never names an alternative explicitly.

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?

There is no when-to-use or when-not guidance and no mention of alternatives such as transit_search_routes or transit_get_timetable. The only usage signal is the implied 'fetch details for a known route' framing carried by the name and the required route parameter.

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