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

Annotations already declare readOnly, idempotent, non-destructive behavior, so safety is covered. The description adds non-obvious behavior: it returns up to five published walks with a specific result shape (distance, walking/listening minutes, ordered stops, audio-guide page, coordinates, deep link). This goes beyond annotations, though it doesn't mention rate limits or pagination.

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-loads the purpose and trigger, then details the return shape. Every sentence earns its place, though the return-shape sentence is dense and could be slightly tightened.

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, so the description must explain returns, which it does thoroughly. Combined with usage boundaries and parameter hints, it is nearly complete for an agent, missing only edge cases like empty results or locale fallback.

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 low (33%), so the description must compensate. It explains the 'query' parameter's meaning beyond the schema: a city, neighbourhood or landmark, not personal details. However, it doesn't describe the 'limit' cap or 'locale' behavior, leaving some parameter semantics to the schema.

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 ('Find self-guided Mappu walking tours') and scopes it to a city, neighbourhood or landmark. The purpose is immediately distinguishable from siblings like mappu_get_audio_guide or mappu_search_public_travel.

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 names the trigger conditions: 'when the traveler wants a walk or asks what to see on foot.' It also sets boundaries by stating it 'covers only walks Mappu has published' and clarifies that a trip plan need not follow them, preempting over-broad use.

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