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

Annotations already cover the read-only, non-destructive, open-world profile, so credit goes to the genuinely additional billing behavior: one credit per successful request even when the result is empty, and repeated requests may purchase the same data again. That is valuable operational context an agent cannot get from the annotations, though the cost statement is muddled by the conflicting "at least 10 Nexscope credits" line.

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 same sentence appears three times, alongside pasted page furniture like "Cosmos Profile API View Pricing" and "1 credit per request." The core fact is front-loaded, but the duplication and copy-paste artifacts make it much longer than the information warrants.

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?

With no output schema, the description does name the payload (bio, links, follower counts) and discloses the credit model, which covers the essentials for a one-parameter lookup. However, the contradictory cost statements (1 credit vs. 'at least 10 Nexscope credits') leave the actual price ambiguous, and nothing explains what is returned when the handle does not exist.

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% and the single 'handle' parameter is already documented as a Cosmos username without a profile URL. The description adds nothing parameter-specific beyond that, which is the expected baseline when the schema carries the parameter fully.

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 and resource plus the returned fields: "Get a public Cosmos profile with bio, links, and follower counts." That is enough to separate it from social_cosmos_post, social_cosmos_search, and social_cosmos_user_posts, though the description never explicitly names those siblings to sharpen the split.

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 only usage constraint given is "Public data only," which tells the agent what is out of scope but not when this tool should be chosen over the neighboring Cosmos tools. There is no guidance about handle formats vs. post IDs, nor any prerequisite or alternative mentioned.

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