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

Annotations already declare readOnlyHint and destructiveHint=false, so the description's real contribution is the partial-success behavior: it returns the posts it found (up to 12) plus the references it could not find. It also discloses that the call uses no credits, which is material in a credit-metered product. It stops short of describing ordering or error semantics beyond the missing-reference case.

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?

Two sentences, front-loaded with the card contents and then the invocation contract. Every clause carries information the agent would otherwise have to guess: sources, key pairing, the 12-item cap, partial-failure handling, and credit cost.

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?

There is no output schema, so the description must explain the return value itself, and it does: found posts in the given order plus unfound references. Combined with the 12-item cap, credit note, and source-to-parameter mapping, an agent has everything needed to call this correctly.

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%, so the baseline is 3, but the description adds the non-obvious pairing constraint that post_keys should be sent together with their originating job_id and that job_id defaults to the latest search. That relationship is not spelled out in the schema and prevents silently rendering keys from the wrong search.

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 ("Displays chosen posts as cards in the chat") and then enumerates exactly what each card contains (platform, handle, views, outperformance, hook/caption, Remake button). That level of specificity makes it unmistakable against siblings like list_my_posts or get_viral_results, which retrieve rather than render.

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?

Names the exact upstream tools that produce valid inputs (find_viral_posts, get_viral_results, load_more_viral, get_feed, get_creator_report) and maps which key type comes from which source. There are no explicit exclusions or when-not-to-use cases, but the routing is unusually concrete for this dimension.

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