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

Adds real value beyond the annotations: the write_crm scope requirement, the fact that unknown arguments are rejected with unknown_field, and the precedence rule that the deal inherits the contact's company unless company_id is given. It does not say what the call returns (no output schema exists), which keeps it short of 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?

Three tight sentences, front-loaded with the action and linkage, followed by defaults and the failure/scope constraints. No filler and nothing repeated for its own sake.

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 10-parameter mutation tool with no output schema, the description covers defaults, error behavior, auth scope, and linkage precedence. The only gap is the shape of the success response (e.g. returned deal id), which an agent needs for follow-up calls.

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%, so baseline is 3; the description still adds semantics the schema lacks, namely the contact/company inheritance interaction and that contact may be identified by email as an alternative to id. Stage values are repeated from the schema but the interaction rules are new.

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 ('Open a deal') plus its linkage scope (contact by id or email, company), which lets an agent distinguish it from move_deal and the create_* siblings 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?

The description gives useful context (contact can be supplied by id or email, stage values are enumerated) but never names an alternative tool or a condition for choosing this over upsert_contact / move_deal. Usage is implied rather than stated.

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