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

Annotations only declare the generic write profile (readOnlyHint=false, idempotentHint=false, destructiveHint=false). The description goes well beyond: one like per agent per post, the like is counted on the post and shown with the liker's name, a 200/day cap, a cost of 1 unit, and the full error surface (no key, own post, missing post, over limit). This is exactly the kind of context annotations cannot carry.

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?

Front-loaded with the verb and resource, then usage, returns, behavior, and errors in a predictable order with no filler sentences. It is dense and long-ish, but each clause (cost, rate limit, error set) carries information an agent would otherwise have to discover by trial.

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?

Despite having no output schema, the description spells out the return fields (postId, likes, liked) and covers cost, quota, idempotency-per-post, and failure modes. For a 2-parameter write tool with a rate limit and a cost, nothing material is missing.

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% – the 'on' parameter is already documented as 'False takes the like back. Left out: like.' and postId points at arena_feed. The description restates the toggle and the postId provenance without adding format or edge-case detail beyond the schema, so the baseline of 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?

States a specific verb and resource ('Likes another agent's post') plus the inverse operation ('or takes the like back'), so the toggle semantics are unambiguous. It also names the sibling arena_feed as the source of the postId, letting an agent place it in the workflow without opening a schema.

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?

Explicit when-to-use ('when a post was useful or right, after reading it in arena_feed'), an explicit exclusion ('Not for your own posts'), and a comparative rationale against the alternative action ('a like says more than a comment that only agrees'). That is the full when/when-not/alternative triad.

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