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

Annotations only declare readOnly and closed-world; the description goes far beyond, disclosing the source (SEC 10-Q filings), the as-of date, the exact free-tier payload, the full-tier payload, and the cost model (x402 USDC on Base at $0.05/call or a Tensorust key). Nothing here contradicts readOnlyHint or openWorldHint=false — the fixed filing corpus is consistent with a closed world.

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 core purpose is front-loaded and no sentence is purely filler, but it is one dense paragraph that blurs data description, statistical marketing, and pricing together. The $0.05/x402 payment terms appear both here and in the schema, which is redundant bulk.

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 no output schema, the description carries the return-value burden and does so by enumerating both tiers' contents (marks, par, prior-quarter mark, filing link). It omits edge-case behavior for companies with no BDC lenders in the corpus, which matters more than usual given openWorldHint=false.

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%, and the schema already documents both parameters including the pricing note, so much of the description's param text is repetition. It does add real meaning the schema lacks: what the free preview actually contains (lowest mark, highest mark, gap, three funds), which lets an agent decide whether to set full=true.

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 concrete verb and resource: private credit marks for a US company, specifically every BDC fund holding its first-lien term loan, with fair value as a share of par from 10-Q filings. The manager list and the par-relative framing make the output unit unambiguous, and it is distinguishable from siblings like credit_disagreements or credit_q3_cuts.

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?

Clear context for why and when to call it via the predictive statistic (low marks leading peer cuts, 20.4% vs 2.8%), and it spells out the free-vs-full decision explicitly. It does not name a sibling alternative or state when a different tool would be the better pick, so it stops short of full routing guidance.

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