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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and openWorld=false, so safety is covered. The description adds genuinely new context: the tool can lazily generate today's brief on demand rather than only reading a pre-existing one, and it discloses the categories of data that come back. It doesn't discuss freshness, latency, or what happens when no brief exists for the requested date.

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?

Two sentences, zero filler. The capability and scope come first, the routing triggers second, and the returned data types are packed into a single list rather than expanded prose.

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 shape need not be described, and annotations already carry the safety profile. For a 3-optional-param, no-required-param read tool, the description covers capability, scope, and invocation triggers with nothing an agent needs left 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 description coverage is 100%, so date, days, and generate are already documented in the schema with formats and defaults. The description adds no parameter-level meaning beyond the schema (e.g., how 'days' interacts with 'date', or whether generate overrides an existing brief), so the baseline of 3 applies.

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 a specific verb+resource ('Get or generate a morning brief'), scopes it ('for the authenticated user's watchlist companies'), and enumerates the payload (overnight announcements, insider trades, price moves, dividends, governance changes). This distinguishes it from market-wide siblings like get_daily_market_wrap and from narrower feeds like get_insider_trades or get_dividends.

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 explicit trigger phrasings — 'morning brief, daily digest, overnight summary, or what happened with their watched companies' — which is clear when-to-use guidance. It stops short of naming an alternative (e.g., get_daily_market_wrap for non-watchlist coverage) or stating exclusions, so it is strong but not fully routing.

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