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

The description's "only what changed since the last check" explains the delta semantics, which is meaningful context beyond the annotations and accounts for why readOnlyHint is false and idempotentHint is false (a checkpoint advances on call). It does not disclose auth requirements, rate limits, or what happens on first call with no prior check.

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, front-loaded with the PRO marker and the trigger phrasing, then the scope of the delta. Slightly promotional ("Great to call...") but that clause carries genuine usage value rather than pure filler.

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 not be described, and the annotations cover the safety/open-world profile. The description adequately covers trigger and delta scope; the only unstated prerequisite is that packages/companies must already be watched before this returns anything, which is only implied by "your watched".

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 tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline is 4. No parameter-level claims are made or 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?

States a specific verb+resource+scope: reports what changed since the last check, naming the exact content types (new exploited/likely-exploited issues in watched packages, new SEC filings from watched companies). It is distinguishable from the per-entity brief_* siblings by its delta-across-watches scope, though it never names those siblings explicitly.

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?

"Great to call at the start of every session" gives a clear positive trigger condition for when to invoke this tool. It stops short of naming alternatives (e.g. brief_company/brief_stack for per-entity queries) or stating exclusions, so it is clear context without full routing guidance.

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