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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds the behavioral caveat that earlier point-in-time availability is not assumed, which is useful context beyond the annotations. However, it doesn't disclose pagination behavior, return format, or how 'as_known_at' interacts with the vintage concept.

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 a single sentence plus a short caveat, which is appropriately concise. The key action and resource are front-loaded, and the caveat about point-in-time availability is placed second. It earns its place, though it could add a bit more guidance without becoming bloated.

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 8 parameters, 0% schema coverage, no output schema, and no parameter descriptions, the description is too thin. An agent cannot determine what 'dataset' vs 'series' vs 'entity' mean, how 'as_known_at' works, or what the response looks like. The annotations cover safety but not semantics, so the description is incomplete for a tool of this complexity.

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 0%, so the description must compensate for 8 undocumented parameters. It only hints at 'historical vintage' and 'point-in-time availability', which loosely maps to 'as_known_at' and 'start'/'end', but it doesn't explain the meaning of 'dataset', 'series', 'entity', 'limit', or 'offset'. The description adds minimal value over the bare schema.

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 specific verb ('Read') and resource ('cited observations or a captured historical vintage'), which distinguishes it from analysis/catalog/entities/series tools. However, it doesn't explicitly name a sibling or elaborate on what 'cited observations' means, so it's clear but not fully differentiated.

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 phrase 'Earlier point-in-time availability is not assumed' implies a caution about historical data availability, giving some context for when to use this tool. But it doesn't explicitly state when to use this vs. research_analysis or research_catalog, nor does it provide exclusions or alternative routing.

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