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

Beyond the readOnly/openWorld/non-destructive annotations, the description discloses the credit model: 1 credit per successful request including native empty results, no charge for scraper failures, and zero cost when the terminal cursor is sent. That is exactly the kind of behavioral context annotations cannot carry. It is held back from a 5 by internally contradictory pricing claims — '1 credit per request' alongside 'Completed lookups cost at least 10 Nexscope credits' and 'Actual cost depends on the operation' — which leave the agent unsure of the real spend.

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 the same block of text repeated roughly three times, and one repetition drags in marketing boilerplate ('Cosmos Collection Posts API View Pricing'). The genuinely useful front-loaded sentence is buried under duplicated credit terms, so an agent must parse redundant text to find the tool's purpose.

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 two-parameter read-only lookup, the description covers scope, pagination, and cost, and with no output schema the pagination termination semantics are addressed. But the conflicting credit statements (1 credit vs. at least 10 credits) are unresolved, which is precisely the kind of ambiguity this tool's description should settle.

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 schema already explains that cursor must be passed unchanged, that null terminates, and that the literal "null" returns an empty page without fetching or charging. The description's cursor cost note largely restates that, so it adds little meaning beyond the structured field. Baseline 3 applies when the schema already carries 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 states a specific verb and resource: 'Get public posts saved to a Cosmos collection,' which separates it from siblings such as social_cosmos_user_posts, social_cosmos_search, and social_cosmos_post. It does not explicitly name an alternative tool or state how it differs from those siblings, so it stops short of a 5.

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?

It gives a useful boundary condition — 'Private or login-restricted content is not available' — which tells the agent when this tool will not work. However, it never says when to prefer it over social_cosmos_user_posts or social_cosmos_search, so routing must be inferred from the name and the URL parameter.

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