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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is partly covered. The description adds a genuine non-schema fact — the required project_phases:write scope — but omits the key semantic question for a destructive-flagged mutation: whether omitted fields are preserved or cleared.

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?

Two short, front-loaded sentences; the purpose precedes the auth requirement and neither sentence is padding. Nothing is extraneous, though the brevity is also part of its incompleteness.

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 an 8-parameter mutation tool with no output schema, the description covers purpose and authorization but is silent on partial-update behavior, side effects of destructive changes, and response shape. Annotations carry the safety hints, which keeps this at minimum-viable rather than inadequate.

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 all eight parameters are already documented individually. The description only echoes the required 'id' parameter, adding no format, default, or partial-update semantics beyond the schema.

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 ('Update an existing project phase by ID'), which is unambiguous. It does not, however, distinguish itself from near siblings such as update_project_phase_category or update_project_milestone, so it lands below the sibling-differentiating 5.

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 no when-to-use, when-not-to-use, or alternatives; 'by ID' only implies the target must already exist. An agent learns nothing about when to prefer this over update_project_task or the phase category tool.

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