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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered; the description adds genuine scope context instead — data age is returned, free-floating bikes are summarised rather than listed, e-scooters are out of scope, and per-source attribution is shown. It does not state refresh cadence or failure behavior, so it falls 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?

Front-loaded with the core purpose, then usage triggers, then exclusions and limits — a sensible priority order with no filler. It is on the long side (multiple parenthetical examples and a trigger-phrase list), which slightly exceeds what an agent strictly needs, but each clause carries 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?

With no output schema, the description usefully sketches the return shape — stations with distance and data age, summarised free-floating bikes, per-source attribution. Combined with explicit coverage limits and exclusions, an agent has enough to call correctly, though it omits what happens when no bikes are found in range.

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%, and the parameter docs are unusually strong (place vs lat/lon exclusivity, language defaulting caveat, only_available semantics). The description adds essentially nothing per-parameter beyond restating the radius and station caps already in the schema, 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 ('Returns rentable shared bikes near a place or coordinate') and immediately scopes it: bike-sharing stations with bikes/free docks plus free-floating bikes. Names the covered providers (nextbike incl. KVB Rad, MyRadl, VAG_Rad; Donkey Republic), so an agent can distinguish it from every sibling without opening the schema.

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?

Explicit when-to-use with trigger phrases ('Leihrad', 'Fahrradverleih', 'nächstes nextbike', 'bike share near me') and explicit when-not-to-use, naming the alternatives (find_parking, find_nearby). It also states hard limits (radius ≤ 5 km, ≤ 20 stations) and an exclusion (e-scooters not covered), leaving nothing to inference.

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