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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds only the methodological detail that the estimate is 'bottom-up', not the return structure or any limits; with annotations carrying the burden, this is adequate but thin.

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?

The core sentence is front-loaded, dense, and wastes no words. The trailing URL sentence is promotional rather than operational, which slightly dilutes an otherwise tight definition.

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 arguably should indicate what the calculation returns (TAM/SAM/SOM values and how they relate), but it only names the inputs. For a four-required-parameter calculator with full schema coverage and a clean safety profile, this is workable but leaves the result shape to inference.

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 the baseline is 3. The description restates the four inputs (companies, reachable share, ACV, obtainable share) in prose but adds no units, ranges, or format guidance beyond the schema's own descriptions.

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 ('Build') and resource ('TAM, SAM, and SOM') and enumerates the exact inputs used, making it clearly distinguishable from adjacent siblings like internationalization_market_prioritization_grid or product_market_fit_scoring_grader. An agent can route to it 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?

Listing the input factors implies when the tool applies (bottom-up market sizing), but there is no explicit when-to-use, when-not-to-use, or named alternative among the many sizing/prioritization siblings. Usage is inferable rather than stated.

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