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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, covering the safety profile. The description adds valuable context: case-insensitive ticker matching and the specific fields returned (yield, risk, custody, availability, how to buy, source link, verification date). It also confirms this is a single-record retrieval, not a list operation. No contradictions with annotations.

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 one concise sentence, front-loaded with the primary purpose ('Full record for one instrument by ticker'), followed by a compact list of the record's contents. No filler, no redundancy with annotations or schema.

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 tool has a single parameter with a documented example, a full output schema (so return format is already defined), and annotations covering safety and idempotency, the description provides everything an agent needs: the scope, the lookup method, case-insensitivity, and the set of fields. Nothing essential 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 coverage is 100% for the single ticker parameter, so the baseline is 3. The description adds meaning beyond the schema by noting case-insensitivity and explicitly enumerating the fields included in the full record, which helps the agent understand what the result will contain. This adds value without being redundant.

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 states a clear verb-resource pair: 'Full record for one instrument by ticker' – it names the specific resource (instrument) and the access method (by ticker), with case-insensitivity noted. It clearly distinguishes itself from sibling tools that search or compare multiple assets, since this returns a full record for a single instrument.

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 implies usage: use this when you need the complete record for a single instrument identified by ticker. It doesn't explicitly name alternatives or exclusions, but the context is clear that this is the go-to for full details on one product, as opposed to comparison or search tools. No misleading guidance.

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