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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false. The description adds useful behavioral context by enumerating the return fields (name, status, species, origin, location, episodes, image URL), which informs the agent about the tool's output without needing to inspect the schema.

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?

The description is a single, information-dense sentence. It front-loads the action and resource, then lists the return fields. No filler words or redundant clauses.

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 simple single-parameter read operation, the description is sufficient: it explains the input, the purpose, and the output fields. The existence of an output schema further reduces the need for the description to detail return formats. Minor gap: it does not mention error behavior for invalid IDs, but this is not critical for such a simple tool.

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?

The input schema has 100% coverage with a clear description for the 'id' parameter, including a valid range and an example. The tool description only repeats 'by numeric ID' without adding new semantic details, so the schema carries the full explanatory burden.

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?

The description clearly states the action ('Get'), the specific resource ('a single Rick and Morty character'), and the access method ('by numeric ID'). It distinguishes from sibling tools like search_characters, get_episode, and get_location by targeting a single character with a known ID.

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?

The description implies when to use this tool (when you have a numeric character ID) and the context is clear. It does not explicitly mention alternatives or exclusions, but the 'by numeric ID' phrasing effectively signals that it is not for searching or for episodes/locations.

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