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

Goes beyond the annotations by disclosing a real side effect: any change returns the card to pending review, which the agent cannot infer from readOnlyHint/idempotentHint/destructiveHint. It also flags the API-key requirement. It could still say whether omitted fields are left untouched and what happens when editing a card you do not own.

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 mutable fields, then the side effect and auth requirement in short declarative sentences. The full bilingual duplication of every sentence is wasted tokens for an agent that reads one language, but the structure itself is tight.

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 five-parameter mutation with one required field and no output schema, the description covers scope, the review-state consequence, and auth. A note on partial-update behavior and failure cases for non-owned cards would close the remaining gap.

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%, so every parameter is already documented with its own description and the card_id links back to mycel_my_cards. The description lists the same field names but adds no format or partial-update semantics beyond what the schema supplies, so the baseline of 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 (Update), the exact mutable fields (description / endpoint_url / price_points / capabilities), and the ownership constraint ("a card you own"). This clearly separates it from mycel_my_cards (likely read) and mycel_publish_agent (create).

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?

Implies the usage context via "a card you own" and the API-key requirement, so the agent knows this is owner-scoped editing. However, it never names an alternative or says when-not to use it (e.g., to change card_id or ownership, or to create a card use mycel_publish_agent).

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