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

The annotations already declare readOnlyHint=true, so no contradiction. The description adds value beyond annotations by disclosing the conditional source selection (live vs last_session vs daily) and the invariant that the latest daily bar is always included when available. This gives the agent insight into the response's variability without over-explaining the output.

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 two sentences, front-loaded with 'Composite quote', and every clause adds meaningful detail about the source logic. There is no redundant information or filler. It is compact while fully explaining the tool's behavior.

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?

The tool has a single parameter, an output schema, and clear annotations. The description thoroughly explains the selection logic and the guaranteed inclusion of the daily bar, which covers the key behavioral aspects. For a quote-retrieval tool of this complexity, nothing critical is missing given the structured metadata available.

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% for the single required parameter 'ticker', including an example. The description does not add any additional parameter semantics, but with high schema coverage, the baseline of 3 is appropriate. No extra compensation is needed.

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 defines what the tool returns: a composite quote with specific source selection logic based on publishing state. It explicitly distinguishes this from sibling tools by describing the 'live', 'last_session', and 'daily' fallback behavior. Although it uses a noun phrase rather than an imperative verb, the scope is unambiguous and specific.

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 provides clear context on when each source is used (publishing hours, off-hours, fallback), which implies when this tool is appropriate for getting a quote. However, it does not explicitly name alternatives or state conditions for choosing this tool over sibling tools like snacs_snapshot_get, so it lacks explicit exclusions.

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