Write diary entry

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

The word 'Add' plus 'inner monologue' conveys append-only semantics, which goes beyond the annotations (readOnlyHint=false, idempotentHint=false) by telling the agent it cannot edit or replace prior entries. It stops short of saying whether entries persist across sessions or how many can accumulate, so the mutation profile is only partly characterized.

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 sentences, zero filler, with the primary purpose front-loaded and the routing constraint second. Every clause carries information.

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 simple two-parameter append tool with a fully described schema and no output schema, the description covers purpose, routing, and tone. Minor gaps remain: no mention of persistence, entry limits, or what happens when the 4000-char bound is exceeded.

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% and both parameters (entry, mood_tag) are documented there, including the 'in her voice' tone guidance and snake_case storage note. The description adds nothing about parameter format or the optional mood_tag, 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 a specific verb and resource ('Add a line to the companion's inner monologue') and anchors it to a named store (femboy://diary). It explicitly contrasts with the sibling femboy_remember_fact, so an agent can pick the right tool without opening either 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 positive cases ('reflections about the code, small wins, or mood notes') and an explicit exclusion with the alternative named ('not for facts (use femboy_remember_fact)'). Both the when and the when-not are covered.

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