Get a saved character

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

With readOnlyHint=true already declaring the safety profile, the description adds the useful fact that the tool produces two distinct output representations and that the JSON variant is the one intended for round-tripping through an overwrite save. Since there is no output schema, this disclosure of return shape carries real weight. It omits edge behavior such as what happens for an unknown id.

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 sentence with no filler, and the most important information (what is returned) is front-loaded before the format distinction. Every clause earns its place.

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 two-parameter read with full schema coverage and a readOnly annotation, the definition covers purpose, output modes, and downstream workflow adequately. The only meaningful omission is error behavior for a nonexistent or inaccessible id.

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 100%, so the baseline would be 3; the description earns a notch more by explaining the intent behind the format enum — markdown is for display, JSON is for editing and re-saving — rather than merely restating the enum values. It adds no new detail about the id parameter beyond 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?

The description states a specific verb and resource ('Returns a saved character card') and enumerates the two output representations, which distinguishes it from sibling reads like character_list. It stops short of naming any sibling tool explicitly, so disambiguation relies on the agent's own reasoning about the character_* family.

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 parenthetical does give workflow context — markdown when the card is just to be shown, JSON when it will be edited and re-saved via overwrite — which is genuinely actionable. However, it offers no guidance on how to determine which tool to call versus character_list or character_check, and no prerequisites such as needing an id from a listing call.

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