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

Annotations already establish read-only, idempotent, non-destructive, closed-world behavior, so the description needn't restate safety. It adds genuinely new behavioral context: 'end is exclusive', publication time must be kept distinct from the market period discussed, and returned sections must be inspected for titles/basis/timestamps before describing an item. That is real disclosure beyond the annotation layer.

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-loaded with the triggering condition, then organized under Selection/Presentation/Evidence labels so each block is scannable. The Presentation and Evidence lines are somewhat prescriptive but each carries a distinct instruction, so little is wasted; slightly longer than the minimum needed.

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?

An output schema exists, so return values need no explanation, and the description instead covers the tricky parts: exclusive end, ticker resolution via research_discover, and not inferring relevance from publication date alone. Combined with full schema coverage and rich annotations, an agent has enough to call it correctly.

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% and both parameters are fully documented in the schema, including the exclusive-end and timezone-qualified ISO format. The description reinforces end-exclusivity and the publication-time vs market-period distinction, but adds no syntax or format detail the schema lacks, so it sits at the baseline.

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 ('a ticker's published video chapters on a selected timeline'), and the negative clauses carve out the scope from market-wide or general web video search. It does not name the closest sibling (research_show_videos) directly, so an agent must infer the division of labor from scope language rather than an explicit pointer.

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 clear when-to-use ('the user wants a ticker's published video chapters') plus explicit when-not conditions (market-wide videos, web video search, causal proof). It also prescribes preserving ticker/date context on follow-ups. It stops short of routing the agent to a named alternative tool, which is what a 5 would require.

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