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

No annotations are provided, so the description carries the full burden. It discloses the use of vaulted OAuth token, X API call, and return format including the unconnected state. However, it omits potential issues like token expiration, rate limits, or error conditions.

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, each earning its place: first states purpose, second explains mechanism and return format, third gives concrete use case. No unnecessary words.

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?

Given the low complexity and presence of output schema (return format explicitly listed), the description covers purpose, input (vaguely), mechanism, output, and use case. It lacks prerequisite guidance (e.g., OAuth must be linked) but is otherwise sufficient.

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 50%: only `npub` is described as 'Required. Your Nostr public key'. The description does not clarify `dpop_token` at all, leaving it undocumented. The description fails to compensate for the missing parameter documentation.

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 tool fetches the connected X account's handle and name, specifying the resource (X account) and the action (fetch). It distinguishes itself from siblings like excalibur_get_nostr_profile (Nostr profile) and excalibur_check_oauth_status (OAuth status check).

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 usage for tweet-card preview and mentions OAuth token, indicating a prerequisite, but lacks explicit when-not-to-use or alternatives. It does not guide the agent to check OAuth status first or compare with similar tools.

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