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

Annotations already cover the safety profile (readOnlyHint, idempotentHint), and the description adds real context beyond them: results are deterministic numeric output rather than a rendered page, and inputs are restricted to the user's own mortgages. It does not disclose output shape (which numbers, units, currency) for a tool with no output schema, which keeps it below a 5.

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 core capability, then the routing alternative, then use cases — a sensible order with no filler sentences. The trailing Hebrew trigger list is dense but purposeful for intent matching, so it earns its place despite adding length.

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?

For a read-only comparison over one array parameter with no output schema, the description covers purpose, routing, and input constraints. The main remaining gap is what the returned 'numbers' comprise, which the agent must discover by calling — acceptable but not fully complete.

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 single parameter already documents '2 to 3 mortgage ids'. The description restates the 2-3 cardinality and adds the ownership qualifier ('the user's own'), but supplies no format or validation detail beyond the schema. Baseline 3 applies when the schema does the heavy lifting.

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 concrete verb+resource ('side-by-side deterministic analysis plus market comparison') scoped to '2-3 of the user's own mortgage ids', and explicitly distinguishes itself from generate_comparison_dashboard ('returns numbers, not a page'). An agent can tell it apart from get_market_comparison and generate_comparison_dashboard without opening any 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?

Names the alternative (generate_comparison_dashboard) and the exact condition that selects it ('for a dashboard the user can open'). Adds concrete use-case triggers including Hebrew phrasings for price comparison, refinancing, and early-repayment fees, so intent matching is largely deterministic.

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