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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds a genuinely useful degenerate case: profile null means the brand is not set up yet and plans still work from the brief alone. The trailing 'Read only' restates the annotation and adds no value, keeping it just shy of a 5.

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?

Four sentences, front-loaded with what is returned, then when to call it, then the null edge case, then parameter sourcing. Almost every clause earns its place; the final 'Read only' is redundant against the annotations.

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 describe the return shape — and it does, enumerating the profile facets and the planning ideas, plus what null profile means for downstream planning. An agent has everything needed to call this and interpret the result, including how to obtain the optional ID.

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 optional parameter is fully documented in the schema, including its source (list_accounts) and the multi-brand condition. The description restates nearly the same guidance rather than adding syntax, format, or fallback behavior beyond it, so baseline 3 applies.

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?

Names the specific resource (the brand profile of one social group) and enumerates what it contains — business, place, voice, call to action, plus the brand's own planning ideas. It is clearly distinguishable from list_accounts, which supplies IDs rather than profile content, and from plan_posts, which consumes this data.

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?

Gives an explicit ordering rule ('Read it before plan_posts'), a conditional trigger for using the returned ideas ('when the user has no brief'), and a sourcing rule for the optional parameter ('Pass social_group_id from list_accounts when the connection covers more than one brand'). All three are actionable without inference.

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