memory_save

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

With no annotations, the description must carry the behavioral burden. It does disclose a meaningful trait — the fact lands in a *shared* memory readable by all connected Claude windows — but omits whether saves append or overwrite, whether there are size/count limits, and how the entry is later identified for deletion.

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/where, then when, then how. Little waste; 'Write it clearly and specifically' is mild instruction fluff but still earns its place as content guidance.

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 write tool with no output schema and no annotations, the description covers purpose, trigger, granularity and visibility well enough to call it correctly. Only the append-vs-overwrite and post-save identification details are missing.

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 both parameters are already documented in the schema and the baseline applies. The description adds only the granularity hint ('one important fact') and encourages specificity in the content, which is marginal beyond structured data.

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 ('Save one important fact ... to the shared memory') and bounds scope with examples (preferences, projects, decisions), plus the cross-window visibility detail. It does not explicitly name or distinguish itself from siblings like memory_search/memory_delete, but the write verb makes the distinction inferable.

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 a concrete trigger: 'Use when the user says "remember this" or states something worth keeping.' No exclusions or when-not guidance are offered, and it never routes the agent to memory_search for deduplication, so it stops short of the top band.

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