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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description layers on genuinely new behavioral context: snapshot semantics ('current-snapshot records'), expected latency, mandatory pricing with no free tier, and a prompt-injection warning that endpoint names/urls/on-chain strings are untrusted data. The injection warning is safety-critical and not derivable from any structured field.

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 purpose, then inputs, then cost/latency, then safety — a sensible ordering with no filler sentences. It is dense but each clause carries distinct information, so nothing feels padded.

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?

With zero required parameters, no output schema and full schema coverage, the agent has enough to invoke it correctly; the description supplies the return shape ('matching current-snapshot records'), cost and safety context. It stops short of describing record fields or any pagination/truncation behavior at the cap.

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%, so all five parameters (including the 5,000 hard cap, the json/csv enum and the default null filters) are already documented in the schema. The description only restates them, adding the 'optional' framing but no new syntax or semantics.

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+resource ('export a filtered slice of the index') and enumerates the filterable dimensions, so the agent knows what it retrieves. It never differentiates itself from the very similar siblings query_agent_index and bulk_agent_index, which is the remaining ambiguity.

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?

There is no explicit when-to-use or when-not-to-use statement and no sibling is named as an alternative. The pricing line ('USD 0.25; no free tier') and latency range implicitly tell the agent this is a paid export, which mildly informs a selection decision against free query siblings, but the agent must infer that.

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