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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so the safety profile is covered. The description adds genuinely new behavioral context the annotations cannot: results are researched and sourced, and 'Facts are as of the research date in the result,' warning the agent about staleness. This is real added value beyond structured fields.

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?

One dense sentence, front-loaded with the verb and resource, followed by the return-contents summary and the 'list' escape hatch. The long platform enumeration is bulky but earns its place as a vocabulary list that lets the agent match user phrasing to valid inputs. Slightly overlong but no wasted sentences.

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?

No output schema exists, so the description must convey what comes back, and it does: pricing, feature coverage, key differences, competitor strengths, and sources. Combined with the research-date caveat and the 'list' affordance, an agent has everything needed to call this correctly on the first try.

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 coverage is 100% and the schema already documents the competitor parameter with examples. The description adds meaning beyond the schema by stating that the literal value 'list' returns every platform, a sentinel behavior not obvious from the parameter's example-only description.

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 ('Researched, sourced comparison of Raziel with another investing or startup platform') and enumerates the exact scope: pricing, feature coverage, key differences, where the other platform is stronger, and sources. This is unmistakably distinct from the sibling calculator tools (irr, runway, moic, etc.), none of which perform comparisons.

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 description gives a concrete usage path for discovery ('Pass "list" to see every platform'), which tells the agent how to resolve an unknown competitor name. It does not explicitly state when-not-to-use or name alternatives, but no comparable sibling exists, so the context is clear if not exhaustive.

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