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

Goes well beyond the readOnly/idempotent/destructive annotations: it discloses that missing or wrong credentials error out with no rows, that amounts are not unit-uniform across rails so they must not be summed, and that results are returned as both structuredContent and JSON text. That unit-mixing caveat is exactly the kind of non-obvious trait annotations cannot express.

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-loads the purpose, then routing, then return caveats, so the important content lands first. It is dense but the row-field enumeration and the limit restatement are slightly more than strictly needed, keeping it out of the top band.

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 3-param read tool with an output schema and full annotation coverage, the description covers routing, auth failure behavior, return shape, and the critical amount-unit pitfall. Nothing an agent needs to call it correctly is missing.

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 the default/clamp/non-integer behavior for limit is already fully documented in the schema and the description only restates it. No parameter meaning is added beyond the schema, which is the baseline-3 case.

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 and resource with scope ("Read your own credit, USDC, and voucher-rail transaction rows, newest first") and explicitly distinguishes itself from siblings by naming get_balance and get_referral_code. An agent can identify this as the ledger-read tool without opening any schema.

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?

Gives explicit when-to-use routing: "Use drinkedin_get_balance when you only need the current voucher and USDC balances" and "use drinkedin_get_referral_code for your own code." Both the alternative and the condition that selects it are stated, plus an exclusion (no referral stats).

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