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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), but the description adds genuinely useful behavior: the estimate's derivation source and the accuracy caveat that branching rules may shorten the real path. It does not discuss caching, rate limits, or staleness of the estimate, which would have pushed it to 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?

One compact passage, front-loaded with what is returned, then the accuracy caveat, then the usage routing. Every sentence carries distinct information with no restatement of the title or schema.

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?

An output schema exists and the description still names the key fields, so nothing about return shape is missing. For a one-parameter read-only lookup with annotations covering safety, the description is fully sufficient to call the tool correctly.

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?

A single required parameter with 100% schema description coverage; the schema already explains that projectId resolves via list_projects. The description adds no new parameter-level meaning, so the baseline 3 applies.

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 the exact metric returned (`estimatedCompletionTimeSeconds` / `estimatedCompletionTimeMinutes`), its derivation basis (question types and AI follow-up depth), and its nature (a rough upper bound). It also distinguishes itself from the sibling `project_overview`, which carries the same figure, so the agent can tell the two apart without opening schemas.

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?

Explicitly names the triggering condition ('when the user asks how long a survey/project takes') and names the alternative (`project_overview already includes the same figure`), effectively signalling when this call is redundant. That is as close to a when/when-not/alternative statement as a single-purpose read tool needs.

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