application_get_activity_instance

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, signaling a safe read operation. The description adds valuable context beyond annotations by noting the raw path workaround due to missing library types and explicitly listing the return fields. This gives the agent a solid behavioral model without contradicting the annotations.

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 extremely concise and well-structured with clear sections: Purpose, Note, and Returns. Every sentence earns its place, providing essential information without any fluff or redundancy.

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?

The tool has a simple input schema (2 params), output schema present, and annotations cover safety. The description explains the purpose, the API path workaround, and return shape, making it complete for an agent to understand what this tool does and what it returns without ambiguity.

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%, with both parameters documented (application_id pattern and instance_id max length/description). The description doesn't add extra parameter semantics beyond what's already in the schema, so the baseline score of 3 is appropriate.

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 the specific action: 'Fetch a running Activity instance by id' and explicitly mentions the Discord Activities API. This uniquely identifies the tool's purpose and clearly distinguishes it from the many sibling tools by resource type ('Activity instance').

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 makes it clear this tool is for fetching an activity instance by ID, providing direct context for when it would be used. It doesn't explicitly mention alternatives or when not to use it, but given there are no similar sibling tools for activity instances, the context is clear enough.

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