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

Annotations already establish read-only/idempotent/safe behavior, and the description adds meaningful non-redundant context: rows are immutable and append-only, stable signal ids are preserved, the latest publication is the default, an active subscription is required, and data is completed EOD rather than real-time or advice. No contradiction 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?

Three sentences earn their place: the first defines the row content and stability guarantees, the second covers defaults and options, the third states prerequisites and data timing. Key qualifiers like 'exact', 'immutable', and 'not real-time or advice' are front-loaded with no redundancy.

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 read-only, idempotent list-style tool with a full output schema and fully documented parameters, the description covers row contents, default behavior, filtering, subscription requirement, and data freshness. Nothing critical for correct invocation 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?

The input schema covers 100% of parameters, so the baseline is 3. The description's mentions of symbol filtering, pagination, and latest-publication default align with schema fields but do not add new semantic meaning beyond what the schema already provides.

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 names the resource precisely—exact immutable agent-facing signal rows for one append-only publication—and details what is included (stable signal ids, previous-row links, changed-field classifications). This is clearly distinct from sibling list/publication tools by emphasizing 'one append-only publication' and frozen/immutable semantics.

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?

It gives clear context for when the tool is appropriate: defaults to the latest publication, supports symbol filtering and pagination, requires an active subscription, and returns completed end-of-day data rather than real-time or advice. It does not name sibling alternatives or state explicit when-not-to-use rules, which keeps it just below a top score.

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