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

The description discloses the payment gating behavior (returns a payment requirement until provided with payment, bundle_token, or api_key), which is a key behavioral trait beyond the name. With no annotations, it partially covers the safety/access profile but omits details like rate limits, error handling, or exact output format, which the description alone should 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?

Two sentences with no filler. It front-loads the price and URL, states the default, and covers authentication paths efficiently. Every sentence 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 tool with no output schema, the description should clarify what the return contains beyond the high-level 'hourly trend series'. It covers payment and default hours but lacks specifics on response structure, edge cases (e.g., invalid hours, limits), and error behavior. Since annotations are absent, this is a noticeable gap, though the core calling requirements (auth, hours) are present.

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 0%, so the description must explain parameters. It does: hours (default 24h), payment (payment header), bundle_token (prepaid), and api_key (free-tier). This adds meaningful semantics beyond the schema's bare string fields, though it doesn't provide constraints like valid hour ranges.

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 clearly states the tool returns an hourly XLM sentiment trend series (Fear & Greed + momentum, order-flow overlaid) with a default 24h window. This specific verb-resource combination distinguishes it from siblings like get_xlm_sentiment (current value) and get_fear_greed_index (index), making the purpose unambiguous.

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 provides context on payment requirements and mentions that a free-tier api_key can be minted via get_free_api_key, guiding authentication. However, it does not explicitly state when to prefer this over siblings (e.g., when a time series is needed vs. a current snapshot), leaving some inference to the agent.

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