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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, and the description goes further by disclosing the reduced payload for a deprecated place and the exact { "error": "not_found" } shape for an unknown slug. With no output schema, this is exactly the return-shape and edge-case context the description must carry, and it does.

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 main behavior and followed by the two exception branches; nothing is redundant. The field enumeration in sentence one is long, but it substitutes for a missing output schema, so it earns its space.

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?

For a single-parameter read tool with no output schema, the description covers return contents, the deprecated-place variation, the not-found case, and the citable canonical URL. An agent can call it correctly and interpret every likely response without opening anything else.

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%, including the slug pattern, length bounds and a concrete example with the note that search_places and places_near return slugs. The description adds only the word 'slug' and no format guidance beyond 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 every fact Little Milwaukee holds about one place by its slug') and enumerates the payload fields, so an agent knows this is the detail-fetch counterpart to the search tools. It is clearly distinguishable from search_places/places_near, which the slug parameter references.

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?

Usage is only implied: the description says it fetches by slug but never explicitly says 'use this after search_places/places_near to expand a result,' and gives no when-not guidance. Branch behavior for deprecated and unknown slugs is documented, which helps an agent interpret outcomes but doesn't route tool selection.

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