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

With no annotations, the description carries the burden and does well: it discloses the API key requirement, the 20-credit-per-image cost, and the shape of the return value. It stops short of stating whether the operation mutates anything server-side or how failures are reported, which matters for a paid call.

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?

Three sentences, each earning its place: capability, then return shape, then cost/alternative. The most decision-relevant constraint (cheaper alternative) is placed where it will be read, with no filler.

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?

The detailed return-value description compensates well for the absent output schema, and the auth/cost notes cover the operational side. The remaining gap is the licensing filter parameters, which are the main thing an agent could get wrong when calling this tool.

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 only 40%, so the description needed to compensate and does not. Three filters (no_credit, commercial_only, include_profanity) and the count/alternatives relationship go entirely unexplained, leaving the licensing semantics of no_credit vs commercial_only — which overlap confusingly — undocumented in both places.

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?

Specific verb and resource ('Reads an article') plus an unusually precise statement of what comes back: matched spots, a chosen image with alternatives, and the article re-emitted as Markdown with images inserted. It is clearly distinguishable from search_memes, which returns candidates rather than placements.

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?

Explicitly names the alternative (calling search_memes per spot) and the condition that selects it: if the agent can read the article itself, the per-spot route is far cheaper. The cost differential (20 credits vs 1 credit) makes the routing decision concrete rather than advisory.

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