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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds valuable behavioral context: it reveals the output includes a 'found=false' case when the provider isn't in the tracked window, and specifies that results are newest-first. This goes beyond the annotations, though it doesn't detail the exact structure of each epoch entry.

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 with zero filler. The first sentence front-loads the core purpose and scope; the second adds usage guidance and input validation. Every clause earns its place.

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 simple read-only tool with two parameters and no output schema, the description is complete. It covers purpose, usage, expected output traits (trend, ordering, found=false), and prerequisites. An agent can confidently select and invoke this tool without additional clarification.

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 0%, so the description must compensate. It explains that 'address must be a 0x EVM address' (matching the schema pattern) and that the tool returns 'up to 30, newest first' epochs, implicitly defining the 'limit' parameter's effect. It adds semantic meaning (trend, ordering) beyond the bare schema, though it doesn't explicitly name the 'limit' parameter.

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 ('Return'), a specific resource ('per-epoch reward-rate and composite-score trend'), and a clear scope ('one Flare FTSO provider', 'most recent tracked reward epochs'). It explicitly names the sibling tool it complements (get_ftso_provider_metrics), making the purpose unambiguous and distinct.

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 explicitly instructs when to use this tool versus the alternative: 'Use this for performance trend over time; use get_ftso_provider_metrics for the current snapshot.' It also states the required address format, eliminating ambiguity about input prerequisites.

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