purchase_filing

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

With no annotations provided, the description fully discloses the tool's behavior: it requires an on-chain payment via 402 workflow, calls must be made in two phases, and the output includes alpha_signals and financial_metrics. It explicitly states what is not returned (agent_bundle or internal pipeline fields).

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?

The description is well-structured with clear sections: purpose, cost, output, workflow, examples. It is somewhat lengthy but every sentence adds value. Minor redundancy could be trimmed, but overall effective.

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?

Given the complexity of the 402 payment workflow, the description is highly complete: it explains the multi-step process, expected output, cost, parameter usage, and what not to include. Schema and output schema support completeness.

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 100%, but the description adds significant meaning: document_id origin (search_filings or get_filing_sample), network default and alternative, and crucial instruction to leave tx_hash empty on first call. Example arguments further clarify usage.

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 purchases and delivers one full SEC filing row from fi_listings_portfolio. It distinguishes from siblings get_filing_sample and search_filings, which are for browsing/finding filings, by focusing on the purchase action.

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?

The description explicitly provides a mandatory 2-step 402 flow with step-by-step instructions, example arguments for minimal and maximal calls, and cost details. It clearly indicates when to use the tool (after finding a filing) and how to perform the payment workflow.

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