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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so safety is covered. The description adds genuine behavioral framing beyond that: the comparison is case-based rather than ratio-based, and response_mode=plain yields a beginner-oriented rendering. It does not describe return structure or length, but the added analytical framing is real value.

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-loads what the tool produces, then triggers, then exclusions, then args. Dense but each clause earns its place; the trigger-phrase list is slightly listy but functional rather than padding.

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 no output schema, the description carries the burden of describing results, and it does identify the comparison contents (valuation, investment case, supports/challenges). It is slightly thin on output shape or length, but an agent has enough to select and 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%, so entities, reading_level and response_mode are already fully documented with their semantics and defaults. The description only restates the entities cardinality ('Args: entities (2-5)') and one mode hint, adding essentially nothing beyond the schema — the baseline 3 for high coverage 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?

States a specific verb and resource ('Two or more companies side by side') and enumerates exactly what is produced — valuation, investment case, supporting and challenging factors. It explicitly distinguishes itself from the single-company sibling ('Not for: one company → answer'), so an agent can route without opening the schema.

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 concrete trigger phrasings ('X vs Y', 'which is the better buy', 'is X or Y more defensive') and an explicit exclusion routing to the answer tool. Both the use case and the boundary case are stated, leaving nothing to inference.

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