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

Beyond the readOnly/openWorld annotations, the description discloses three non-obvious behaviors: CSV formula-injection escaping for cells starting with = + - or @, a Pro-plan requirement, and a hard truncation cap at 400,000 characters (a real data-loss risk). These are exactly the operational facts annotations cannot convey.

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 sentences, front-loaded with what the tool produces, followed by the security behavior and the gating/limit facts. No filler and nothing repeated from the 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?

Although there is no output schema, the description enumerates the returned columns and format, plus the escaping and truncation behavior. Combined with complete parameter docs and read-only annotations, an agent has everything needed to invoke it 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?

Schema description coverage is 100%, so every one of the 7 parameters is already documented, including enum values and defaults. The description adds no filter syntax or format detail beyond that, so the baseline of 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 a specific verb (exports), a specific resource (detail lines of a date range), and the exact output format and column set (CSV: date, project, client, task, person, hours, billable, rate per hour). This clearly separates it from siblings like export_data, export_invoices_csv, and get_time_report 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?

The phrase 'with the same filters and visibility as the time report' implies a relationship to get_time_report, but never states when to export versus call that report, nor when to prefer export_data/export_invoices_csv. Usage is implied rather than directed.

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