code_activity

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

Annotations already declare readOnly/idempotent/non-destructive and closed-world, so the safety profile is covered. The description adds real context beyond that: results carry diff excerpts, results are silently empty without a watched code folder, and it names the config artifacts (automatic-capture.json, code_workspaces) that control that behavior.

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?

Front-loads what the tool returns, then the filter axes, then the caveat about watched folders. Dense but every clause carries information; slightly long for a single paragraph, with the caveat tucked at the end where it is easiest to miss.

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?

With an output schema present, the description need not explain return fields, and it correctly focuses on filtering, diff excerpting, and the empty-result precondition. Nothing essential for a correct call is missing, though the default limit/max_diff_chars tradeoffs are only in the schema.

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 63%; the description supplies meaning for the undocumented parameters by naming the filter set (project, happened_from/happened_to as ISO, file, symbol, kind) and tying them to example queries. limit and max_diff_chars are left to their schema text, which already documents them.

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+resource: code changes recorded by the capture service, with diff excerpts, plus the filter axes (project, time range, file, symbol, kind). This is clearly distinct from the brain_* sibling tools, so an agent can select 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?

Gives two concrete example questions ('what did I change in auth.py last week?', 'when did the parser change?') that map directly onto the filters, and states the precondition that results are empty unless a code folder is being watched. It does not name any alternative tool to prefer or avoid, but no sibling overlaps this domain.

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